Automotive air conditioner having condenser and evaporator provided within air duct

ABSTRACT

An automotive air conditioner which conditions air making use of radiation of heat of a condenser and absorption of heat of an evaporator effectively. The evaporator 207 and the condenser 203 are disposed in a duct 100. A bypass passageway 150 is provided sidewardly of the condenser 203 in the duct 100, and a flow rate of air bypassing the condenser 203 is controlled by pivotal motion of an air mixing damper 154. Another bypass passage is provided sidewardly of the evaporator 207 in the duct 100, and a flow rate of air bypassing the evaporator 207 is controlled by pivotal motion of a bypass damper 159. Air is conditioned to an optimum blown out air temperature by varying the cooling rate at the evaporator 207 and the heating rate at the condenser 203 and is blown out to a room of an automobile from spit holes 141, 142 and 143. An outside heat exchanger is provided outside the duct 100, and a flow of refrigerant is changed over suitably among the outside heat exchanger 202, the evaporator 207 and the condenser 203 to perform cooling operation, heating operation, dehumidifying operation, dehumidifying heating operation and defrosting operation.

This is a division of application Ser. No. 08/781,047, filed Jan. 9,1997 now U.S. Pat. No. 5,782,102, which is a division of applicationSer. No. 08/332,062 filed Nov. 1, 1994, now U.S. Pat. No. 5,642,627,which is a division of application Ser. No. 08/138,207 filed Oct. 20,1993, now abandoned, which is a division of application Ser. No.07/873,430 filed Apr. 24, 1992, now U.S. Pat. No. 5,299,431 issued Apr.5, 1994.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an automotive air conditioner for conditioningair in a room of an automobile. The automotive air conditioner of thepresent invention is effectively applied to an automobile which does nothave a surplus heat source such as, for example, an electric automobile.

2. Description of the Prior Art

Usually, an automotive air conditioner makes use, in order to heat air,of heat from cooling water for an engine for driving an automobile.However, heating of air is performed using a heat pump when the amountof heat of cooling water for an engine is insufficient or when anautomobile does not originally have engine cooling water such as anelectric automobile.

For example, in an automotive air conditioner disclosed in JapanesePatent Laid-Open Application No. 60-219114, a flow of refrigerant ischanged over by means of a four-way valve such that an inside heatexchanger is used either as an evaporator to cool air or as a condenserto heat air.

With the automotive air conditioner wherein cooling operation andheating operation are performed alternatively by changing over of afour-way valve in this manner, since the single heat exchanger changesits function immediately between a function of an evaporator and anotherfunction of a condenser, there is the possibility that, particularlywhen the function is changed over, a large amount of moisture may beblasted from a surface of the inside heat exchanger toward the inside ofthe room of the automobile.

In particular, water condensed on a surface of the inside heat exchangerduring cooling operation is evaporated from the surface of the insideheat exchanger as a result of changing over to heating operation andthen carried into the room of the automobile by a blower. Such blastingof a large amount of water will instantaneously fog a windshield and/orwindow glass. The fog will make an obstacle to a field of view indriving the automobile and is very inconvenient.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an automotive airconditioner for an automobile, which has an engine of the type whereinengine cooling water does not make a sufficient heat source or has nosurplus heat source such as an electric automobile, wherein desirableair conditioning can be performed making full use of a variation of heatinvolved in condensation and evaporation in a refrigerating cycle.

Particularly, according to the present invention, heat exchangersdisposed in a duct are specified in function as a heater and anevaporator so that it is prevented that a single heat exchangeralternatively functions as a heater or an evaporator. In other words, itis another object of the present invention to provide an automotive airconditioner which prevents such a situation even when an operating modein air conditioning is changed over that a large amount of moisture isevaporated to cause fogging of the windshield of an automobile and soforth.

It is a further object of the present invention to provide an automotiveair conditioner wherein the capacity of a compressor can be variablycontrolled by driving the compressor by means of an electric motor andair conditioning can be performed efficiently with a low power bysuitably controlling the discharging capacity of the compressor andre-heating of air by means of a heater.

It is a still further object of the present invention to provide anautomotive air conditioner wherein cooling operation or heatingoperation can be performed efficiently by controlling a flow ofrefrigerant to an outside heat exchanger which is provided to complementthe capacities of a heater and an evaporator disposed in a duct.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein cooling operation, dehumidifyingoperation and heating operation can be performed effectively by variablycontrolling an air flow bypassing an evaporator and a heater disposed ina duct by means of a damper.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein cooling operation, dehumidifyingoperation and heating operation can be achieved by suitably controllinga flow of refrigerant discharged from a compressor between an evaporatorand a heater disposed in a duct and an outside heat exchanger disposedoutside the duct.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein cooling operation, dehumidifyingoperation and heating operation can be achieved better by varying theheat exchanging capacities of an outside condenser and an outsideevaporator provided to complement the condensing and evaporatingfunctions of a heater and an evaporator.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation thereof can be changedover between heating operation in which refrigerant circulates in theorder of a compressor, a heater, decompressing means and an outside heatexchanger and dehumidifying operation in which the refrigerant flows inthe order of the compressor, the heater, the outside heat exchanger, thedecompressing means and an evaporator by changing over the flow of therefrigerant and heating operation can be maintained while preventingfogging up of the windshield and so forth by changing over the operationsuitably to dehumidifying operation when necessary even in a conditionof heating operation.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation is changed over betweena heating operation condition and a dehumidifying operation condition bychanging over means and defrosting of an outside heat exchanger can beachieved by changing over, even in a heating operation condition, theoperation to a dehumidifying operation condition in a condition whereinit is forecast that the outside heat exchanger may be frosted.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the operation is changed over betweena heating operation condition and a dehumidifying operation condition bychanging over means and defrosting of an evaporator can be achieved wellby changing over, even in dehumidifying operation, the operation toheating operation in a condition wherein it is forecast that theevaporator may be frosted.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the condensing pressure ofrefrigerant in a heater can be varied to control the temperature of theheater by performing condensing of the refrigerant, in dehumidifyingoperation, by both of the heater and an outside heat exchanger andvarying the condensing capacity of the outside heat exchanger.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the pressure of refrigerant in anevaporator is prevented from dropping below a predetermined valuethereby to prevent fogging up of an inside evaporator by providing aflow of refrigerant which bypasses the inside evaporator and changingover the refrigerant between a flow which flows to the inside evaporatorside and another flow which flows to the bypass passageway by means of asolenoid valve.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein high pressure side refrigerant in arefrigerating cycle can have a sufficient subcooling degree andefficient operation of the refrigerating cycle can be performed bydividing an inside heater into a plurality of inside heaters and usingthe inside heater on the upstream side of a refrigerant flow as acondenser which performs condensing of the refrigerant while using theinside heater on the downstream side of the refrigerant flow as asubcooler which performs radiation of heat of condensed high pressureliquid refrigerant.

It is a yet further object of the present invention to provide anautomotive air conditioner wherein the amount of heat to be absorbedupon operation of a heat pump is increased to enhance the heatingcapacity by using an inside heater as a condenser and using both of aninside evaporator and an outside heat exchanger as evaporators when theheating load is high such as upon starting of heating operation under alow temperature and particularly when heating by inside air circulationis performed.

It is a yet further object of the present invention to provide anautomatic air conditioner wherein an inside heater is divided into aninside condenser and an inside subcooler and throttling amount controlof expanding means can be performed appropriately even in a conditionwherein refrigerant does not substantially flow into either of theinside condenser and the inside subcooler in a cycle in which thethrottling amount of the expanding means is varied so that apredetermined subcooling amount may be obtained with the insidesubcooler.

It is a yet further object of the present invention to provide anautomatic air conditioner wherein a receiver for suitably absorbing avariation of a flow rate of refrigerant which circulates in arefrigerating cycle can be installed well in the refrigerating cycle.

It is an additional object of the present invention to provide anautomatic air conditioner wherein, even in case frost is detected an asurface of an evaporator when dehumidifying operation is to beperformed, defogging of the evaporator can be performed withoutinvolving a great variation of the temperature of air to be blasted.

In order to attain the objects, according to the present invention, theconstruction is employed wherein an evaporator and a heater whichconstitute a refrigerating cycle are disposed in a duct which defines anair passageway.

Further, according to the present invention, a bypass passageway isformed sidewardly of a heater in a duct, and the amount of air to passthe bypass passageway and the amount of air to pass the heater arevariably controlled continuously using an air mixing damper.

Further, according to the present invention, the cooling capacity of anevaporator in a duct and the heating capacity of a heater in the ductare suitably controlled by suitably controlling a flow and a flow rateof refrigerant to flow into the heater and the evaporator in the ductand also into an outside heat exchanger outside the duct.

Further, according to the present invention, a compressor is driven byan electric motor, and the speed of rotation of the electric motor iscontinuously controlled by a controller to variably control thedischarging capacity of a compressor.

Further, according to the present invention, an outside heat exchangeris disposed outside a duct so that the heat exchanging performance of aheater or an evaporator may be complemented by the outside heatexchanger.

Further, according to the present invention, changing over means isdisposed so that a flow of refrigerant passing an outside heat exchangermay be changed over in response to an operation condition required forthe automotive air conditioner, that is, a heating operation conditionor a cooling operation condition.

Further, according to the present invention, an outside heat exchangeris divided into an outside condenser used only for condensation and anoutside evaporator used only for evaporation and varying means areprovided for varying the condensing function of the outside condenserand the evaporating function of the outside evaporator.

Further, according to the present invention, changing over means isprovided so as to effect changing over control among a cooling operationcondition wherein refrigerant circulates in the order of a compressor,an outside heat exchanger, decompressing means and an evaporator, aheating operation condition wherein refrigerant circulates in the orderof the compressor, the heater, the decompressing means and the outsideheat exchanger and a dehumidifying operation condition whereinrefrigerant circulates in the order of the compressor, the heater, theoutside heat exchanger, the decompressing means and the evaporator.

Further, according to the present invention, in a condition wherein itis forecast that the windshield of a room of an automobile is fogged,changing over means is controlled to be driven to change over theoperation from a heating operation condition to a dehumidifyingoperation condition.

Further, according to the present invention, in a condition whereinfreezing of an evaporator is forecast, changing over means is controlledto be driven to change over the operation from a dehumidifying operationcondition to a heating operation condition.

Further, according to the present invention, means is provided forchanging over, in a condition wherein freezing of an outside heatexchanger is forecast, refrigerant to be admitted into an outside heatexchanger from a low pressure condition after passing expanding means toa high pressure condition before passing the expanding condition.

Further, according to the present invention, means for varying thecapacity of an outside heat exchanger is provided, and upondehumidifying operation in which both of the outside heat exchanger anda heater perform condensation of refrigerant, the capacity of theoutside heat exchanger is varied to vary the condensing temperature ofthe heater.

Further, according to the present invention, a bypass passageway forflowing refrigerant bypassing an inside evaporator is provided, and aflow of refrigerant is controlled to be changed over by a solenoid valvebetween a flow which flows to the inside evaporator side and anotherflow which flows to the bypass passageway side.

Further, according to the present invention, an inside heater is dividedinto a plurality of inside heaters, and the inside heater on theupstream side in a flow of refrigerant operates as an inside condenserwhile the inside heater on the downstream side in a flow of refrigerantfunctions as an inside subcooler.

Further, according to the present invention, an inner heater functionsas a condenser while an outside heat exchanger functions as anevaporator upon heating operation, and when the heating load isparticularly high, changing over of a flow of refrigerant is controlledso that also the inside evaporator operates as an evaporator togetherwith the outside heat exchanger.

Further, according to the present invention, such a construction isemployed that an inside heater is divided into an inside condenser andan inside subcooler to achieve a refrigerating cycle in which thethrottling amount of an expansion valve is controlled so that apredetermined subcooling degree can be obtained, and refrigerant flowsinto the inside subcooler upon heating operation and upon dehumidifyingoperation.

Further, according to the present invention, such a construction isemployed that a refrigerating cycle wherein a receiver is disposed onthe upstream side of expanding means in a flow of refrigerant is formedand the location of the receiver is always positioned on the upstreamside of the expanding means even if the operation is changed over to anyof cooling operation, heating operation or dehumidifying operation.

Further, according to the present invention, an automotive airconditioner adopts such a construction that, when a frosted condition ofan evaporator is forecast or detected upon dehumidifying operationwherein a heat exchanger on the upstream side in a duct functions as arefrigerant evaporator and another heat exchanger on the downstream sidein the duct functions as a refrigerant condenser, the condition of anoutside heat exchanger is changed over between a condition wherein it isnot used as a heat exchanger between refrigerant and air or it is usedas a refrigerant condenser to another condition wherein it is used as arefrigerant evaporator.

Because the construction described above is employed, with theautomotive air conditioner, the evaporator disposed in the duct onlyperforms cooling of air while the heater disposed in the duct onlyperforms heating of air. Accordingly, such a situation is eliminatedthat a single heat exchanger alternatively performs cooling of air orheating of air in accordance with an operation condition. Besides, sincecooling of air by the evaporator and heating of air by the heater areused in combination, appropriate temperature control can be achievedwhile performing dehumidification of air.

Further, with the automotive air conditioner, the cooling capacity canbe varied to vary the temperature of air after passing the evaporator byvariably controlling the discharging capacity of the compressor.

Further, with the automotive air conditioner, while the outside heatexchanger is disposed outside the duct and performs heat exchangingbetween outside air and refrigerant, the heat exchanging function of theheater or the evaporator by changing over a flow of refrigerant to flowto the outside heat exchanger between a flow of refrigerant to flow tothe heater and a returning flow of refrigerant from the evaporator. Inthis instance, the outside heat exchanger has a function as a condenseror a function of an evaporator by changing over the flow of refrigerant.However, since the outside heat exchanger performs heat exchangingbetween air outside the duct and refrigerant, even if moisture isproduced by a large amount at some location upon changing overoperation, this will not make an obstacle to driving of the automobileor the like.

Further, with the automotive air conditioner, since the bypasspassageways are provided sidewardly of the evaporator and the heater andthe ratio of a flow rate of air flowing through either one of the bypasspassageways to another flow rate of air flowing through the evaporatoror the heater is controlled by the damper, cooling of air and heating ofair in the duct can be controlled. As a result, useless cooling anduseless re-heating of air can be eliminated.

Further, with the automotive air conditioner, since the outside heatexchanger is divided into the outside condenser and the outsideevaporator installed separately, also the outside heat exchanger isalways specified in function. and the outside condenser and the outsideevaporator are installed at optimum locations in accordance withrespective functions. Further, in this instance, since the varying meansis employed for varying the heat exchanging functions of the outsidecondenser and the outside evaporator, the functions of the condenser andthe evaporator installed in the duct can be variably controlled inconnection with the functions of the outside condenser and the outsideevaporator.

Further, with the automotive air conditioner, since the bypass passagefor flowing refrigerant bypassing the evaporator is provided and a flowof refrigerant is controlled to be changed over between the evaporatorside and the bypass passageway side, when the pressure of refrigerant inthe evaporator becomes lower than a predetermined value, refrigerant canbe flowed to the bypass passageway side. Since refrigerant does not flowthrough the evaporator when refrigerant flows to the bypass passagewayside, the pressure of refrigerant in the evaporator rises as a result.Then, when the pressure of refrigerant in the evaporator rises higherthan the predetermined value, refrigerant is changed over so that it maybe flowed to the evaporator side again. The pressure of refrigerant inthe evaporator can be controlled to the predetermined value byperforming such changing over as described just above.

Further, with the automotive air conditioner, since the inside heater isformed separately as a heat exchanger which functions as a condenser andanother heat exchanger which functions as a subcooler for subcoolingcondensed liquid registrant, refrigerant on the high pressure side inthe refrigerating cycle can have a sufficiently high subcooling degree,and efficient operation of the refrigerating cycle can be performed.

Further, with the automotive air conditioner, upon heating operation,radiation of heat is performed by the inside heater while the insideheat exchanger serves as an evaporator in which absorption of heat isperformed, and when the heating load is particularly high such as uponstarting of heating in a low temperature condition, refrigerant passesalso through the evaporator so that absorption of heat may be performedalso in the evaporator. The heating capacity can be enhanced byincreasing the amount of heat absorption in this manner.

Further, with the automotive air conditioner, the inside heater isdivided into the condenser and the subcooler, and a temperature sensingtube is provided for varying the throttling amount of the expandingmeans so that the subcooling degree of refrigerant on the exit side ofthe inside condenser may be substantially constant in order thatrefrigerant passing the subcooler may have a predetermined subcoolingdegree. In the refrigerating cycle having such a construction asdescribed just above, even in a condition wherein no refrigerant flowsinto the inside condenser and the inside subcooler, operation of therefrigerating cycle can be performed with certainty by employing a fixedthrottle in addition to throttling for the expanding means provided bythe temperature sensing tube.

Further, with the automotive air conditioner, since, upon dehumidifyingoperation, the heat exchanger on the upstream side in the duct functionsas a refrigerant evaporator and the heat exchanger on the downstreamside in the duct functions as a refrigerant condenser, when air passesthrough the evaporator on the upstream side, it is cooled, whereuponsaturated vapor is removed from the air, whereafter it is heated when itpasses through the heater on the downstream side, and after then, it isblasted into the room of the automobile. Then, if the temperature of theevaporator drops to a temperature at which frosting occurs or to atemperature near to such temperature at which frosting occurs, thecontrolling apparatus detects or forecasts such frosting by means of thefrost sensor. Then, the controlling apparatus controls the flow passagechanging over means to change over the outside heat exchanger from acondition wherein the outside heat exchanger is not used as a heatexchanger between refrigerant and air or is used as a refrigerantcondenser to another condition wherein the outside heat exchanger isused as a refrigerant evaporator.

Then, since the evaporator and the outside heat exchanger both functionas refrigerant evaporators, the evaporating pressure is raised, andfrosting of the heat exchanger on the upstream side is prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view showing a preferred embodiment of thepresent invention;

FIG. 2 is a Mollier chart illustrating an operating condition of theautomotive air conditioner shown in FIG. 1;

FIG. 3 is a diagrammatic view showing another preferred embodiment ofthe present invention;

FIG. 4 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 3;

FIG. 5 is a diagrammatic view showing a further preferred embodiment ofthe present invention;

FIG. 6 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 5;

FIG. 7 is a diagrammatic view showing a still further preferredembodiment of the present invention;

FIG. 8 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 7 in a cooling condition;

FIG. 9 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 7 in a heating condition;

FIG. 10 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 7;

FIG. 11 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 12 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 11;

FIG. 13 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 14 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 15 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 14 in cooling operation;

FIG. 16 is a Mollier chart illustrating an operation condition of theautomotive air conditioner shown in FIG. 14 in a heating condition;

FIG. 17 is a diagram illustrating an example of control of theautomotive air conditioner shown in FIG. 14;

FIG. 18 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 19 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 20 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 21 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 22 is a Mollier chart illustrating operation of the automotive airconditioner shown in FIG. 21;

FIG. 23 is a Mollier chart illustrating another operation of theautomotive air conditioner shown in FIG. 21;

FIG. 24 is a Mollier chart illustrating a further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 25 is a Mollier chart illustrating a still further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 26 is a Mollier chart illustrating a yet further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 27 is a Mollier chart illustrating a yet further operation of theautomotive air conditioner shown in FIG. 21;

FIG. 28 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 29 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 30 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 31 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 32 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 33 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 34 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 35 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 36 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 37 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 38 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 39 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 40 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 41 is a flow chart illustrating an example of refrigerating cyclecontrol of the present invention;

FIG. 42 is a flow chart showing another form of the flow chart shown inFIG. 41;

FIG. 43 is a flow chart showing a further form of the flow chart shownin FIG. 41;

FIG. 44 is a flow chart showing a still further form of the flow chartshown in FIG. 41;

FIG. 45 is a flow chart showing a yet further form of the flow chartshown in FIG. 41;

FIG. 46 is a flow chart showing a yet further form of the flow chartshown in FIG. 41;

FIG. 47 is a flow chart showing another example of refrigerating cyclecontrol of the present invention;

FIG. 48 is a flow chart showing a further example of refrigerating cyclecontrol of the present invention;

FIG. 49 is a flow chart showing another form of the flow chart shown inFIG. 48;

FIG. 50 is a diagram illustrating a form of control of a blower for anoutside heat exchanger of a refrigerating cycle of the presentinvention;

FIG. 51 is a flow chart illustrating an example of control when arefrigerating cycle of the present invention is used in dehumidifyingoperation;

FIG. 52 is a front elevational view showing an example of operationpanel used in the present invention;

FIG. 53 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 54 is a flow chart illustrating an example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 55 is a flow chart illustrating another example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 56 is a flow chart illustrating a further example of control of theautomotive air conditioner shown in FIG. 53;

FIG. 57 is a flow chart illustrating a still further example of controlof the automotive air conditioner shown in FIG. 53;

FIG. 58 is a flow chart illustrating a yet further example of control ofthe automotive air conditioner shown in FIG. 53;

FIG. 59 is a table illustrating operation modes of the automotive airconditioner shown in FIG. 53 and operating conditions of components ofthe same;

FIG. 60 is a diagrammatic schematic view showing a flow of refrigerantupon heating operation of the is automotive air conditioner shown inFIG. 53;

FIG. 61 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying heating operation of the automotive air conditionershown in FIG. 53;

FIG. 62 is a diagrammatic schematic view showing a flow of refrigerantupon cooling operation of the automotive air conditioner shown in FIG.53;

FIG. 63 is a diagrammatic schematic view showing a flow of refrigerantupon defrosting operation of the automotive air conditioner shown inFIG. 53;

FIG. 64 is a front elevational view showing an example of operationpanel of the automotive air conditioner shown in FIG. 53;

FIG. 65 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 66 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 67 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 68 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 69 is a diagrammatic view showing a yet further preferredembodiment of the present invention;

FIG. 70 is a diagrammatic schematic view showing a flow of refrigerantupon heating operation of the automotive air conditioner shown in FIG.69;

FIG. 71 is a diagrammatic schematic view showing a flow of refrigerantupon cooling operation of the automotive air conditioner shown in FIG.69;

FIG. 72 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying heating operation of the automotive air conditionershown in FIG. 69;

FIG. 73 is a diagrammatic schematic view showing a flow of refrigerantupon dehumidifying defrosting operation of the automotive airconditioner shown in FIG. 69;

FIG. 74 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 75 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 76 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 77 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 78 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 79 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 80 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 81 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 82 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 83 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention;

FIG. 84 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention; and

FIG. 85 is a refrigerant circuit diagram of an air conditioner accordingto a yet further embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, embodiments of the present invention will be describedwith reference to the drawings. Referring to FIG. 1, a duct 100 whichdefines an air passageway is disposed in a room of an automobile. A fancase 101 is connected to an end of the duct 100, and a blower 132 isdisposed in the fan case 101. The blower 132 is driven to rotate by amotor 133 disposed at a central location thereof. An inside/outside airchanging over section 130 is connected in the fan case 101, and aninside air inlet port 134 and an outside air inlet port 135 are openedat the inside/outside air changing over section 130. An inside/outsideair changing over damper 131 is disposed in the inside/outside airchanging over section 130, and air to be introduced into the duct 100can be changed over between inside air and outside air of theautomobile.

The duct 100 has a plurality of spit holes formed at an end portionthereof for blowing out conditioned air into the room of the automobile.The spit holes include a vent spit hole 144 for principally blowing outa cool wind toward the head and breast portions of passengers, a footspit hole 145 for principally blowing out a warm wind toward the legs ofpassengers, and a def spit hole 146 for principally blowing out a warmwind toward the windshield. A vent damper 143, a foot damper 143 and adef damper 141 are provided at the spit holes 144, 145 and 146 forcontrolling air flows to the spit holes 144, 145 and 146, respectively.

An evaporator 207 of a refrigerating cycle is disposed in the duct 100,and a condenser 203 of the refrigerating cycle is disposed on thedownstream side of the evaporator 207 similarly in the duct 100. It isto be noted that the evaporator 207 operates as a cooler which takesheat of vaporization away from air for conditioning or air upon heatexchanging thereby to cool the air. Meanwhile, the condenser 203operates as a heater which radiates heat of condensation to air uponheat exchanging thereby to heat the air.

A bypass passageway 150 is disposed sidewardly of the inside condenser203 in the duct 100, and an air mixing damper 154 is disposed forpivotal motion at an end thereof in the duct 100 for variablycontinuously controlling the ratio between the amount of air flowingthrough the bypass passageway 150 and the amount of air flowing throughthe condenser 203.

It is to be noted that the refrigerating cycle includes a compressor 201which is driven by an electric motor not shown to compress and dischargerefrigerant. Since the compressor 201 is disposed in an enclosed casingintegrally with the electric motor, the location thereof is not limitedto a particular location. It is only preferable for the compressor 201to be disposed at any other location than within the room of theautomobile for the convenience of maintenance and so forth. Refrigerantin a high temperature, high pressure condition discharged from thecompressor 201 is condensed by an outside heat exchanger 202. Theoutside heat exchanger 202 operates only as a condenser and is disposedat a forward location in the advancing direction of the automobile sothat good heat exchanging can be effected with outside air. In otherwords, the outside heat exchanger 202 meets with a driving wind duringdriving of the automobile so that refrigerant thereof can be cooledwell. Meanwhile, the condenser 203 is coupled to the outside heatexchanger 202 by way of a refrigerant pipe. Liquid refrigerant condensedby passage through the condenser 203 flows once into a receiver 205. Thereceiver 205 has a comparatively great volume so that it can keepsurplus refrigerant in the form of liquid therein. An interface betweengas and liquid appears in the receiver 205, and only liquid refrigerantis delivered to expanding means 206 side. The expanding means 206 is, inthe present automotive air conditioner, a temperature differentialexpansion valve which varies the throttling amount thereof in responseto a degree of superheat of refrigerant on the exit side of theevaporator 207. In particular, the expansion valve 206 receives a signalfrom a temperature sensing tube 204 and varies the throttling amountthereof in response to the signal so that the superheat on the exit sideof the evaporator 207 may normally be constant. The expansion valve 206is disposed in the proximity of the evaporator 207. On the other hand,while the location of the receiver 205 described above is notparticularly limited, it is preferably disposed outside the room of theautomobile, for example, in the engine room for the convenience ofmaintenance and so forth.

An operation panel 300 is disposed at a location within the room of theautomobile at which it can be visually observed readily by a passenger.The operation panel 300 includes a fan lever 301 for controlling thespeed of rotation of the blower motor 133, a temperature adjusting lever302 for controlling the opening of the air mixing damper 154, a modechanging over lever 303 for controlling the spit hole dampers 142, 143and 141, an operating lever 304 for controlling the inside/outside airchanging over damper 131 to make a changing over operation, an airconditioner switch 305 for starting operation of the automotive airconditioner, an economy switch 306 for causing the automotive airconditioner to operate in a power saving mode, and an off switch 307 forstopping operation of the automotive air conditioner.

A temperature sensor 322 detects a temperature of air on the exit sideof the evaporator 207, and normally the discharging amount of thecompressor 201 is controlled in accordance with a signal from thetemperature sensor 322 so that the temperature of air on the exit sideof the evaporator 207 may range from 3 to 4 degrees. However, when theeconomy switch 306 is switched on, the discharging amount of thecompressor 201 is variably controlled in response to a signal from thesensor 322 so that the air temperature on the exit side of theevaporator 207 may range from 10 to 11 degrees.

A sensor 323 detects a pressure of refrigerant on the upstream side ofthe expanding means 206. A refrigerant pressure detected by the sensor323 is substantially equal to a pressure of refrigerant in thecompressor 203, and a saturation condensation temperature of refrigerantin the condenser 203 is calculated from the pressure.

Subsequently, operation of the automotive air conditioner having suchconstruction as described above will be described.

If the air conditioner switch 305 is switched on and the fan switch 301is set to any of positions LO, MID and HI, then the compressor 201starts its rotation and the fan motor 133 is rotated at a selectedspeed. Gas refrigerant in a high temperature, high pressure conditiondischarged from the compressor 201 is condensed at part thereof in theoutside heat exchanger 202 and condensed at the remaining part thereofin the condenser 203 disposed in the duct 100. Refrigerant thuscondensed into liquid is then separated from gas in the receiver 205,and only the liquid refrigerant is supplied to the expanding means 206.The liquid refrigerant is adiabatically expanded into mist of a lowtemperature and a low pressure by the expanding means 206 and thensupplied into the evaporator 207. In the evaporator 207, the mistrefrigerant exchanges heat with air supplied thereto from the blower132. In particular, the mist refrigerant takes heat of vaporization awayfrom the air so that it is vaporized while it remains in a low pressurecondition. The thus vaporized gas refrigerant is sucked into thecompressor 201 again.

FIG. 2 is a Mollier chart illustrating an operation condition of therefrigerating cycle. A solid line in FIG. 2 shows a condition whereinthe air mixing damper 154 assumes its fully open position as shown inFIG. 1. In other words, the solid line shows a condition whereinblasting air flows into the condenser 203. As seen from FIG. 2,condensation is performed by the outside heat exchanger 202 and thecondenser 203. In this condition, an enthalpy ΔI obtained in thecondenser 203 is consumed for heating of air, and accordingly, airhaving passed the evaporator 207 and the condenser 203 will perform acooling action by an amount corresponding to an enthalpy Ie.

A broken line in FIG. 2 shows a condition wherein the air mixing damper154 assumes its fully closed condition. In this condition, no flow ofair is introduced into the condenser 203. Accordingly, condensation ofrefrigerant is performed all by the outside heat exchanger 202. In thisinstance, however, since the effective capacity of the heat exchangersis decreased by the capacity of the condenser 203, the pressurenecessary to condense refrigerant is increased. In particular, thepressure on the discharging side of the compressor 201 is increased alittle. On the other hand, the pressure on the sucking side of thecompressor 201 is maintained constant independently of the opening ofthe air mixing damper 154 because it is controlled by the expandingmeans 206.

Then, in such a condition wherein the air mixing damper 154 is in afully closed position as indicated by the broken line in FIG. 2, sincethe loss in enthalpy by the condenser 203 can be ignored, the coolingfunction of the evaporator 207 can be used as it is for cooling.

Subsequently, a condition of a flow of air in this instance will bedescribed. Air selectively supplied by the inside/outside changing overdamper 131 is supplied into the evaporator 207 by the blower 132. Here,when the air passes the evaporator 207, it is cooled by vaporization ofrefrigerant so that it has a temperature ranging from 3 to 4 degrees onthe exit side of the evaporator 207, and in this condition, it comes tothe bypass passageway 150 and the condenser 203.

The air flow is suitably selected by the air mixing damper 154. Inparticular, in a condition wherein maximum cooling is required, the airmixing damper 154 closes the condenser 203 so that the cooled air isintroduced as it is to the spit hole side. In case it is desired toraise the temperature of air to be blown out, the air mixing damper 154is opened so that part of the air may be introduced into the condenser203. Air introduced into the condenser 203 is re-heated in the condenser203 to a predetermined temperature and then mixed, in an air mixingchamber 155, with air having passed the bypass passageway 150.

The thus conditioned air is blown out into the room of the automobilefrom a selected one or ones of the dampers 142, 143 and 141. When themode switch 303 is at its vent mode position, only the vent damper 142is opened while the other dampers 143 and 141 remain closed.Consequently, a cooling wind will be blown out principally to the headand breast portions of passengers. On the other hand, when the modeswitch 303 is at its bi-level mode position, the def damper 141 isclosed while the vent damper 142 and the foot damper 143 are opened.Consequently, a warm wind having passed the condenser 203 will be blownout principally from the foot spit hole 145 toward the feet ofpassengers while a cooling wind having passed the bypass passageway 150is blown out principally from the vent spit hole 144 toward the head andbreast portions of the passengers.

When the mode lever 303 is brought to its foot mode position, only thefoot damper 143 is opened while the other dampers 142 and 141 areclosed. As a result air having passed the condenser 203 is blown outfrom the foot spit hole 143 toward the feet of passengers.

When the mode lever 303 is set to its def mode position, only the defdamper 141 is opened while the other dampers 142 and 143 are closed. Asa result, dehumidified air having passed the condenser 203 is blown outfrom the def spit hole 146 toward the windshield of the automobile.

It is to be noted that, in the automotive air conditioner describedabove, when the mode lever 303 is set to the foot mode position, airhaving passed the condenser 203 will be blown out as it is to the footportions of passengers. Here, as seen from the Mollier chart of FIG. 2,in the condition described above, the difference in enthalpy at theevaporator 207 is greater by a predetermined amount Ie than thedifference in enthalpy at the condenser 203. However, since aconsiderable part of the cooling capacity of the evaporator 207 isconsumed to condense moisture in the air on a surface of the evaporator207, air having passed the evaporator 207 and the condenser 203 willrise in temperature. In particular, even if the temperature of theoutside air is low, since air cooled when it passes the evaporator 207is re-heated in the condenser 203, the temperature of air when it passesthe condenser 203 is raised to 20 to 25 degrees or so. However, sincethe temperature is comparatively low as a temperature of air to be blownout upon heating, it is desirable, in an operating condition whereinheating is required, to use a PCT heater and some other auxiliary heatsource.

While the receiver 205 in the automotive air conditioner of FIG. 1 isdisposed on the downstream of the condenser 203, it may otherwise bedisposed on the downstream of the outside heat exchanger 202 as shown inFIG. 19. In this instance, condensation of refrigerant is completed atthe outside heat exchanger 202, and the heat exchanger 203 acts as asubcooler which radiates heat of high temperature, high pressure liquidrefrigerant introduced thereinto from the receiver 205. Accordingly, inthe present invention, the heat exchanger disposed in the duct 100 isnot necessarily limited to the condenser 203, but includes a subcooler.Accordingly, in the present invention, a condenser, a subcooler or thelike which radiates heat of high temperature, high pressure refrigerantwill be generally referred to as a heater.

Further, while, in the automotive air conditioner of FIG. 1, the openingof the air mixing damper 154, the speed of rotation of the blower motor133 and the speed of rotation of the compressor 201 are set by manualoperations of a passenger of the automobile, they may otherwise be setautomatically. FIG. 3 shows such an automatic automotive airconditioner. Referring to FIG. 3, a sensor 361 detects a temperature ofoutside air, and another sensor 362 measures a temperature of air in theroom of the automobile. A solar radiation sensor 363 measures an amountof the sunlight incident into the room of the automobile, and atemperature sensor 364 measures a temperature of blown out air. Anothertemperature sensor 365 is disposed on the exit side of the condenser 203and measures a temperature of air having passed the condenser 203.

An example of control of the automatic automotive air conditioner willbe described subsequently with reference to FIG. 4 which illustrates aflow chart of the control. If switching on of the air conditioner switch305 is detected at step 401, then inputs from the various sensors arereceived at step 402. Then, a necessary blown out air temperature Tao iscalculated in accordance with the inputs at step 403. Then at step 404,it is determined in accordance with a value of the necessary blown outair temperature Tao whether or not the operation of the compressor 201should be in an economy mode. In particular, if the necessary blown outair temperature Tao is equal to or higher than a predetermined value,for example, 20 degrees, the temperature Teo at the exit of theevaporator 207 is set to a higher temperature side preset temperature,for example, to 10 degrees. On the other hand, when the necessary blownout air temperature Tao is lower than another predetermined value, forexample, 10 degrees, the air temperature at the exit of the evaporator207 is set, at the lower temperature side thereof, to another presettemperature, for example, to 3 degrees.

Then at step 405, a temperature Te of air at the exit of the evaporator207 is received from the sensor 322. The temperature Te thus received atstep 405 and the air temperature Teo obtained at step 404 are comparedwith each other at step 406. When the actual blown out air temperatureTe is higher than the aimed blown out air temperature Teo, this is acondition wherein a higher capacity is required for the refrigeratingcycle, and consequently, the frequency of an inverter not shown israised at step 407 to increase the discharging capacity of thecompressor 201. On the contrary when the actual temperature Te is lowerthan the aimed temperature Teo, this is a condition wherein the capacityof the refrigerating apparatus is excessively high, and consequently,the frequency of the inverter is lowered at step 408 to decrease thedischarging capacity of the compressor 201. Variation of the dischargingcapacity of the compressor 201 is performed when the aimed temperatureTeo is lower than the higher temperature side preset temperature, forexample, 10 degrees, and the routine described above is repeated by wayof step 409. Then, in case it is judged at step 409 that the aimedtemperature Teo is higher than the higher temperature side presettemperature, the control sequence advances to step 410, at which theopening of the air mixing damper 154 is controlled. While the opening ofthe air mixing damper 154 is controlled in accordance with the aimedtemperature Tao, it is influenced further by a temperature ofrefrigerant in the condenser 203. In particular, when a pressure ofrefrigerant obtained from the pressure sensor 323 is high, it is judgedthat also the temperature of refrigerant is high, and in this instance,even if the aimed temperature Tao is equal, the opening of the airmixing damper 154 is varied so that the air mixing damper 154 may bepivoted by a smaller amount.

In particular, in the present automotive air conditioner, as control ofa cooling operation, the discharging capacity of the compressor 201 isfirst varied to achieve power saving operation and then the air mixingdamper 154 is pivoted so that the temperature control may be availableto the high temperature side.

Referring now to FIG. 5, there is shown a further automotive airconditioner according to the present invention, in which therefrigerating cycle is an accumulator cycle. In particular, anaccumulator 212 for accumulating refrigerant therein is installed on theexit side of the evaporator 207 and the sucking side of the compressor201, and a capillary tube 211 of a fixed throttle is employed in placeof the expansion valve as the expanding or decompressing means. In thisinstance, since the capillary tube 211 does not require an excessiveinstallation area, it is disposed in the duct 100.

FIG. 6 is a Mollier chart of the automotive air conditioner shown inFIG. 5. A solid line in FIG. 6 illustrates a condition wherein the airmixing damper 154 is opened fully so that cooling air is introduced intothe compressor 203. Meanwhile, a broken line in FIG. 6 illustratesanother example wherein the air mixing damper 154 is closed so that thecondenser 203 may not substantially perform a condensing operation. Alsowith the present automotive air conditioner, it can be seen that,similarly as with the automotive air conditioners of the precedingembodiments described above, the pressure on the higher pressure siderises a little when the air mixing damper 154 is closed. Further, sincethe refrigerating cycle is an accumulator cycle, superheat is not takenon the exit side of the evaporator 207. Instead, a predeterminedsubcooling degree is obtained on the exit side of the condenser 203.

FIG. 7 shows a still further automotive air conditioner of the presentinvention, in which the outside heat exchanger 202 can be changed oversuch that it is used as a condenser or as an evaporator in accordancewith the necessity. In particular, referring to FIG. 7, a first four-wayvalve 213 and a second four-way valve 214 are disposed at the oppositeend portions of the outside heat exchanger 202. The first four-way valve213 is changed over between a first connecting condition (indicated by asolid line) wherein interconnects the discharging side of the compressor201 and the outside heat exchanger 202 and interconnects the suctionside of the compressor 201 and the refrigerant pipe 220 and a secondconnecting condition (indicated by a broken line) wherein itinterconnects the discharging side of the compressor 201 and therefrigerant pipe 220 and interconnects the outside heat exchanger 202and the sucking side of the compressor 201.

Also the second four-way valve 214 is changed over between a firstconnecting condition indicated by a solid line in FIG. 7 and a secondconnecting condition indicated by a broken line in FIG. 7. In the firstconnecting condition, the second four-way valve 214 interconnects theoutside heat exchanger 202 and the condenser 203 and interconnects theevaporator 207 and the sucking side of the compressor 201. On the otherhand, in the second connecting condition, the second four-way valve 214interconnects the refrigerant pipe 220 and the condenser 203 andinterconnects the evaporator 207 and the outside heat exchanger 202.

It is to be noted that, in the automotive air conditioner shown in FIG.7, since it has a condition wherein the evaporator 207 and the outsideheat exchanger 202 are connected directly to each other, an evaporationpressure regulating valve 208 is disposed on the downstream of theevaporator 207.

Subsequently, an operation condition of the automotive air conditionshown in FIG. 7 will be described with reference to Mollier charts ofFIGS. 8 and 9. FIG. 8 illustrates a condition wherein the first andsecond four-way valves 213 and 214 assume their respective firstconnecting conditions and the outside heat exchanger 202 acts as acondenser. The condition is used principally upon cooling operation insummer. The condition is basically similar to that of the Mollier chartshown in FIG. 6, and the variation in enthalpy at the condenser 203 isadjusted in response to the opening of the air mixing damper 154.

FIG. 9 illustrates another condition wherein the first and secondfour-way valves 213 and 214 assume the respective second connectingconditions on the contrary. In the present condition, the outside heatexchanger 202 is used as an evaporator, and the present condition isused principally for heating operation in winter. In this instance,refrigerant discharged from the compressor 201 is supplied to thecondenser 203 by way of the refrigerant pipe 220. Condensation ofrefrigerant is performed only by the condenser 203. Accordingly, a greatenthalpy difference is obtained at the condenser 203, and consequently,a sufficient amount of heat can be radiated. Refrigerant condensed intoliquid by the condenser 203 is decompressed and expanded when it passesthe capillary tube 211 and is supplied in the form of mist into theevaporator 207. Evaporation of refrigerant is performed by theevaporator 207 and the outside heat exchanger 202.

It is to be noted, however, that the pressure of refrigerant in theevaporator 207 is maintained constant since the evaporation pressureregulating valve 208 is disposed on the downstream of the evaporator207. In is particular, it is prevented that the pressure of refrigerantin the evaporator 207 is lowered excessively so that the temperature ata surface of the evaporator 207 drops to a temperature lower than -2° C.to cause freezing of the surface of the evaporator 207. Particularly inwinter, there is the possibility that, upon admission of outside air,the temperature of the evaporator 207 may be dropped excessively.However, where the evaporating pressure regulating valve 208 is disposedin this manner, otherwise possible freezing of the evaporator 207 can beprevented with certainty. On the contrary, when refrigerant passes theevaporating pressure regulating valve 208, the pressure thereof isfurther dropped such that the evaporating temperature in the outsideheat exchanger 202 becomes lower than the freezing point. Consequently,freezing likely occurs at the outside heat exchanger 202. In order toprevent freezing at the outside heat exchanger 202, high temperaturerefrigerant on the discharging side of the compressor 201 should besupplied to the outside heat exchanger 202 at suitable time intervals.

It is to be noted that, in the automotive air conditioner shown in FIG.7, the first and second four-way valves 213 and 214 are controlled bychanging over of the switches 306, 310 and 311. In particular, in acondition wherein the cooler switch 310 or the economy switch 306 is on,the automotive air conditioner performs cooling operation with the firstand second four-way valves 213 and 214 set to the respective firstconnecting conditions. On the other hand, in another condition whereinthe heat switch 311 is on, the first and second four-way valves 213 and214 assume the respective second connecting conditions, and theautomotive air conditioner performs heating operation.

It is to be noted that it is also possible to modify the automotive airconditioner shown in FIG. 7 into an automatic automotive air conditioneremploying a microcomputer. In this instance, sensors similar to thoseshown in FIG. 3 may be employed, and the discharging capacity of thecompressor 201, the opening of the air mixing damper 154 and changingover operations of the first and second four-way valves 213 and 214 arecontrolled by way of the controller 300. Such control will be describedwith reference to FIG. 10. After an aimed blown out air temperature Taois calculated at step 403 in accordance with inputs received at step 402from the various sensors, it is judged at step 411 in accordance withthe aimed blown out air temperature Tao whether cooling operation orheating operation should be performed. In case a cooler mode isdetermined, the first and second four-way valves 213 and 214 are changedover to the respective first connecting conditions indicated by solidlines in FIG. 10 at step 412. In the cooler mode, control of a blown outair temperature is executed using steps 405, 406, 407, 408, 409 and 410similar to those of the cycle shown in FIG. 4.

In case a heater mode is determined at step 411, the first and secondfour-wary valves 213 and 214 are changed over to the respective secondconnecting positions indicated by broken lines in FIG. 10 at step 413.In the heater mode, the air mixing damper 154 is basically held in afully open condition, and to this end, an instruction is delivered atstep 414 to fully open the air mixing damper 154. At step 415 afterthen, a pressure of refrigerant is inputted from the sensor 233 and acondensing temperature at the condenser 203 is calculated in accordancewith the refrigerant pressure. Then, a condensing temperature Tcobtained from the sensor 365 is compared at step 416 with the aimedtemperature Tao calculated at step 403. In case the condensingtemperature Tao is higher, the control sequence advances to step 417, atwhich the frequency of the invertor is lowered to decrease thedischarging capacity of the compressor 201. On the contrary in case thecondensing temperature Tc is lower, the frequency of the invertor israised at step 418 to increase the discharging capacity of thecompressor 201. In this manner, in the operation illustrated in FIG. 10of the automotive air conditioner, power saving operation of thecompressor 201 by control of the invertor takes precedence in either ofthe cooler mode and the heater mode.

FIG. 11 shows a yet further automotive air conditioner according to thepresent invention. While the evaporator 207 in all of the automotive airconditioners described above is disposed such that it occupies theentire air passing position in the duct 100, it is disposed, in thepresent automotive air conditioner, such that a bypass passageway 160may be formed sidewardly of the evaporator 207 in the duct 100. Further,a bypass damper 159 is disposed for pivotal motion in the duct 100 sothat the rate between an amount of air flowing in the bypass passageway160 and another amount of air flowing in the evaporator 207 may becontrolled by means of the bypass damper 159. Construction of the otherportion of the automotive air conditioner is similar to that of theautomotive air conditioner described hereinabove with reference to FIG.7.

Accordingly, in the automotive air conditioner shown in FIG. 11, theflow rate of air to flow into the evaporator 207 principally uponheating operation can be decreased by means of the damper 159. Since theblown out air temperature of the evaporator 207 is that for cooling ofair even upon heating, if the flow rate of air to pass the evaporator207 is decreased by means of the damper 159 in this manner, then theheating capacity is enhanced as much.

Subsequently, an example of control of the controller 300 in theautomotive air conditioner shown in FIG. 11 will be described. Thepresent control is characterized particularly in control of the openingof the damper 159. In the flow chart of FIG. 12, control of the damper159 is executed when a heater mode is determined at step 411. In otherwords, in case a cooler mode is determined at step 411, the damper 159closes the bypass passageway 160 so that the entire amount of air fromthe blower 132 may pass the evaporator 207.

When a heater mode is determined at step 411, a necessary dehumidifyingamount is calculated at step 419. The necessary dehumidifying amount iscalculated depending upon whether or not the inside/outside air changingover damper 131 is in an inside air admitting condition and inaccordance with an amount of a wind of the blower 132, a relativehumidity in the room of the automobile and so forth. Then, at step 420,the damper 159 is continuously controlled in accordance with thenecessary dehumidifying amount. In particular, when the necessarydehumidifying amount is great, air is introduced into the evaporator 207to increase the dehumidifying amount of the evaporator 207. Then, afterpivoting control of the damper 159 is executed at step 420, thedischarging capacity of the compressor 201 is varied by varying thefrequency of the invertor similarly as in the control describedhereinabove with reference to FIG. 4, thereby controlling the blown outair temperature. Also in this instance, the air mixing damper 154 is inthe fully open condition so that the entire amount of air is flowed intothe condenser 203.

Accordingly, with the automotive air conditioner shown in FIG. 11,cooling operation and heating operation can be performed well, andparticularly upon heating operation, the heating efficiency can beenhanced by restricting the function of the evaporator 207 to a minimumlimit necessary for dehumidification.

An automotive air conditioner according to a yet further embodiment ofthe present invention will be described subsequently with reference toFIG. 13. The present automotive air conditioner includes fourth checkvalves 216, 217, 218 and 219 in place of the second four-way valve 214described hereinabove.

In the following, description will be given of functions of the checkvalves. When the first four-way valve 213 is at the first connectingposition indicated by a solid line in FIG. 13, high pressure refrigerantdischarged from the compressor 201 comes to the check valves 216 and 218by way of the outside heat exchanger 202. Then, due to a function of thecheck valve 218, the refrigerant will not flow to the evaporationpressure regulating valve 208 side but will all flow to the condenser203 side past the check valve 216. After then, the refrigerant isdecompressed by the decompressing or expanding means 211 and introducedto the evaporation pressure regulating valve 208 and the check valve 219by way of the evaporator 207. The check valve 218 on the downstream ofthe evaporation pressure regulating valve 208 can mechanically flowrefrigerant therethrough toward the downstream of the evaporationpressure regulating valve 208. However, since the downstream of thecheck valve 218 is in a high pressure condition on the discharging sideof the compressor 201 as described hereinabove, the low pressurerefrigerant cannot pass the check valve 218. On the other hand, sincethe check valve 219 is communicated with the low pressure side of thecompressor 201 by way of the accumulator 212, refrigerant can pass thecheck valve 219 readily. Accordingly, refrigerant will all be returnedto the compressor 201 past the check valve 219.

Subsequently, a flow of refrigerant when the first four-way valve 213 isin the second connecting position indicated by a broken line in FIG. 13will be described. In this instance, refrigerant in a high pressurecondition discharged from the compressor 201 comes to the check valves219 and 217. Then, the flow of refrigerant is stopped by the check valve219, and consequently, all of the refrigerant flows to the check valve217 side. Then, the flow of the refrigerant having passed the checkvalve 217 is stopped by the check valve 216, and consequently, all ofthe refrigerant flows to the condenser 203 side.

The refrigerant having flowed through the condenser 203 is then put intoa low pressure condition when it passes the decompressing means 211 andthen flows to the evaporation pressure regulating valve 208 side by wayof the evaporator 207. Thus, since the check valve 219 is acted upon atan end thereof by a high pressure on the discharging side of thecompressor 201, refrigerant after having passed the evaporator 207cannot pass the check valve 219. Accordingly, all of the refrigerantpasses the check valve 218 past the evaporation pressure regulatingvalve 208. The refrigerant having passed the check valve 218 will allflow into the outside heat exchanger 202. This is because the exit sideof the check valve 216 is at a high pressure on the discharging side ofthe compressor 201 and the refrigerant cannot pass check valve 216. Therefrigerant having passed the outside heat exchanger 202 will thereafterreturn to the suction side of the compressor 201 by way of the firstfour-way valve 213.

In this manner, with the automotive air conditioner shown in FIG. 13,the functions of the second four-way valve 213 are substituted by thefour check valves 216, 217, 218 and 219. Accordingly, electric movableelements can be reduced, and consequently, the automotive airconditioner has an improved durability.

Subsequently, a yet further automotive air conditioner of the presentinvention will be described with reference to FIG. 14.

In the automotive air conditioners of the foregoing embodimentsdescribed hereinabove, only one outside heat exchanger, that is, theheat exchanger 202, is employed and is either used as a condenser(embodiments shown in FIGS. 1, 3 and 5) or is changed over between afunction of a condenser and another function of an evaporator,embodiments shown in FIGS. 7, 11 and 13). However, in the automotive airconditioner of the embodiment shown in FIG. 14, two outside heatexchangers are provided including an outside condenser 202 and anoutside evaporator 210. Besides, in the automatic air conditioner of thepresent embodiment, a condensing damper 253 is provided as condensingside varying means so that the flow rate of air to flow into the outsidecondenser 202 may be varied. Similarly, an evaporating side damper 254is provided as evaporating side varying means so that the flow rate ofair to be sucked into the outside evaporator 210 may be variablycontrolled.

In this manner, in the automotive air conditioner of the embodimentshown in FIG. 14, the two outside heat exchangers are always usedindividually as a condenser (outside condenser 202) and an evaporator(outside evaporator 210). Here, the outside condenser 202 is usedprincipally upon cooling operation to cool refrigerant into liquid.Accordingly, preferably the outside condenser 202 is installed, forexample, at a front portion of the automobile so that it may meet with adriving wind of the automobile. In the meantime, the outside evaporator210 is used to evaporate refrigerant principally upon heating.Preferably, the outside evaporator 210 is disposed such that, forevaporation of refrigerant upon heating, it may not meet with a drivingwind of the automobile or the like when the temperature of outside airis low. More particularly, preferably the outside evaporator 210exchanges heat with ventilation air from within the room of theautomobile. Therefore, the outside evaporator 210 is disposedintermediately of a flow of ventilation air at a rear location of theroom of the automobile.

In this manner, with the automotive air conditioner shown in FIG. 14,the outside condenser 202 and the outside evaporator 210 can both bedisposed at respective optimum locations.

Further, since the dampers 253 and 254 are employed in the presentautomotive air conditioner, the heat exchanging capacities of theoutside heat exchangers 202 and 210 for which no function is requiredfor construction of a refrigerating cycle can be minimized. For example,it is demanded, upon cooling operation, that refrigerant be evaporatedonly at the evaporator 207, and in this instance, the evaporator damper254 closes the outside evaporators 214 and 210 so that a flow of air maynot flow into the outside evaporator 210. On the other hand, uponheating operation, it is desirable that condensation of refrigerant beperformed in the condenser 203 disposed in the duct 100, and in thisinstance, the condensing damper 253 closes the outside condenser 202.

Those conditions will be described with reference to the Mollier chartsof FIGS. 15 and 16. FIG. 15 illustrates a cooling condition, in whichrefrigerant compressed to a high pressure by the compressor 201 is firstcondensed by the outside condenser 202 and then condensed by thecondenser 203 disposed in the duct 100. Further, in this condition, theoutside evaporator 210 is substantially prevented from performing heatexchanging by the evaporation damper 254, and consequently, evaporationof refrigerant is performed only by the inside evaporator 207.

On the other hand, FIG. 16 shows a heating condition. In this condition,the condensing damper 253 closes the outside condenser 202, andconsequently, condensation of refrigerant is performed only by theinside condenser 203. The evaporating pressure of the evaporator 207 isregulated by the evaporation pressure regulating valve 208, andevaporation of refrigerant which has been further decompressed uponpassing through the evaporation pressure regulating valve 208 isperformed by the outside evaporator 210.

In the automotive air conditioner shown in FIG. 14, in addition to thedischarging capacity of the compressor 210, the opening of the airmixing damper 54 and the opening of the bypass damper 159, also theopenings of the condensing side damper 253 and the evaporating sidedamper 254 are controlled by the controller 300. The openings and thecapacity are controlled principally in accordance with an aimed blownout air temperature Tao calculated in accordance with values inputtedfrom the various sensors. A concept of the control is illustrated inFIG. 17. The axis of abscissa of FIG. 17 indicates the aimed blown outair temperature Tao, which increases in the rightward direction in FIG.17. In particular, a heating condition is shown at a right-hand sideportion while a cooling condition is shown at a left-hand side portionof FIG. 17.

The location A in FIG. 17 shows a maximum cooling condition, in whichthe capacity of the compressor 210 presents its maximum and the amountof pivotal motion of the air mixing damper 154 is 0, that is, no air isblown to the condenser 203. Meanwhile, the amount of pivotal motion ofthe bypass damper 59 is at its 100%, and consequently the entire amountof air passes the evaporator 207. Further, the condensing side varyingmeans 253 is open to allow air to be admitted into the outside condenser202. In the meantime, the damper 254 on the evaporating side varyingmeans is closed so that no air is admitted into the outside evaporator210. When the cooling capacity required for the automotive airconditioner decreases (point B in FIG. 17) as the cooling load decreasesafter then, the capacity of the compressor 201 is decreased first. Inparticular, the speed of rotation of the compressor driving motor islowered to decrease the cooling capacity so that the temperature of airon the exit side of the evaporator 207 is raised. Consequently, powersaving operation is achieved first. After the capacity of the compressor210 is minimized, the air mixing damper 154 begins to open (point C inFIG. 17) so that air may be re-heated by the condenser 203.

As the aimed blown out air temperature Tao further rises (point D inFIG. 17), the bypass damper 159 begins to close so that air may beflowed to the condenser 203 side bypassing the evaporator 207. Thiscondition corresponds to dehumidifying operation principally in autumnan winter and in an intermediate time.

As the aimed blown out air temperature Tao further rises (point E inFIG. 17) after then, the operation mode of the automotive airconditioner is changed over from cooling operation to heating operation.In particular, the damper 253 which is the condensing side varying meansis closed to stop the function of the outside condenser 202. Meanwhile,the damper 254 which is the evaporating side varying means is opened tocause the outside evaporator 210 to function.

Then, the discharging capacity of the compressor 201 is raised as theaimed blown out air temperature Tao rises to raise the condensingtemperature at the condenser 203 (points F to G in FIG. 17). It is to benoted that, in the heating condition, when the aimed blown out airtemperature Tao is comparatively low, the bypass damper 159 is held in asomewhat open condition so that dehumidifying operation can be performedsimultaneously.

Then, in maximum heating operation (point H in FIG. 17), the dischargingcapacity of the compressor 201 presents it maximum and the air mixingdamper 154 introduces the entire amount of a flow of air into thecondenser 203. Meanwhile, the bypass damper 159 closes the evaporator207 so that air may be flowed to the condenser 203 side bypassing theevaporator 207. Further, the evaporating side varying means 253 stopsthe function of the outside condenser 202 while the evaporating sidevarying means 254 causes the outside evaporator 210 to function.

It is to be noted that, while, in the control described hereinabove withreference to FIG. 17, the condensing side damper 253 and the evaporatingside damper 254 are individually changed over between the fully closedcondition and the fully open condition, is pivotal motion of the dampers253 and 254 may otherwise be controlled continuously if necessary.Further, while, in the automotive air conditioner described above, theair mixing damper 154 begins to open after the discharging capacity ofthe compressor 201 has been minimized, the point of time at which theair mixing damper 154 begins to open may be advanced. In other words,the components described above can be changed suitably if necessary.

Further, while, in the automotive air conditioner shown in FIG. 14, thedampers 253 and 254 are employed as condensing side varying means andevaporating side varying means, respectively, alternatively a condensingfan 261 may be provided as condensing side varying means while anevaporating fan 252 is provided as evaporating side varying means asshown in FIG. 18. In particular, the heat exchanging functions of theoutside condenser 202 and the outside evaporator 210 may be varied bycontrolling rotation of the fans 251 and 252, respectively.

It is to be noted that, while the bypass passageway 150 is formedsidewardly of the condenser 203 in the automotive air conditionerdescribed above, alternatively the entire amount of air in the duct 100may pass the condenser 203 as seen from FIG. 20.

A pair of auxiliary heaters 700 and 701 are disposed on the downstreamof the condenser 203 in the duct 100. Each of the auxiliary heaters 700and 701 may be formed from a PCT heater or an electric heater. In theautomotive air conditioner shown in FIG. 20, cooling operation,dehumidifying operation and heating operation are achieved individuallyby controlling flow rates of refrigerant into the evaporator 207 and thecondenser 203 both disposed in the duct 100.

Referring now to FIG. 21, there is shown a refrigerating cycle of theautomotive air conditioner shown in FIG. 20. In the refrigerating cycleshown, the four-way valve 213 changes over, upon energization thereof,the refrigerating passage in such a manner as indicated by a solid line,but changes over, upon deenergization thereof, to such a manner asindicated by a broken line. Further, the outside heat exchanger 202includes a fan 251.

In the present refrigerating cycle, the four-way valve 213 and thesolenoid valves 260 and 261 are suitably changed over to control a flowof refrigerant to achieve various air conditioning operation. First, acooling operation condition will be described. In this condition, thefour-way valve 213 is energized so that refrigerant discharged from thecompressor 201 is flowed to the outside heat exchanger 202 side by wayof the four-way valve 213 and the check valve 262. Here, the refrigerantmeets with a wind from the fan 251 so that it is condensed in theoutside heat exchanger 202 while remaining in a high temperature, highpressure condition. Meanwhile, the solenoid valve 261 remains closed inthis condition, and accordingly, the refrigerant condensed in theoutside heat exchanger 202 flows into the expanding means 211 and isdecompressed and expanded into mist in a low temperature low pressurecondition when it passes the expanding means 211. The refrigerant in theform of mist then flows into the evaporator 207, in which it isevaporated, whereupon it takes heat of vaporization away fromconditioning air to cool the air.

Then, the refrigerant evaporated in the evaporator 207 is sucked intothe compressor 213 again by way of the accumulator 212. It is to benoted that, in this instance, since the refrigerant passage iscommunicated at a branching point 264 on the upstream of the accumulator212 with the condenser 203 side by way of the four-way valve 213, thecheck valve 265 positioned on the downstream of the condenser 203 closesthe refrigerating passage in accordance with a difference in pressure,and consequently, substantially no refrigerant will flow into thecondenser 203.

It is to be noted that there is no possibility that part of refrigeranthaving flowed to the condenser 203 side may be liquefied and accumulatedin the condenser 203. This is because refrigerant in the condenser 203is sucked into the compressor 201 by way of the four-way valve 213.

Subsequently, a flow of refrigerant when the automotive air conditioneroperates as a heating apparatus will be described. In this instance, thecompressor 201 and the condenser 203 are communicated with each other byway of the four-way valve 213. Meanwhile, the solenoid valve 260 isclosed to cause refrigerant to flow to a capillary element 266 side.Further, the solenoid valve 261 is opened to cause refrigerant from theoutside heat exchanger 202 to flow to the accumulator 212 side.

Accordingly, upon heating operation, refrigerant put into a hightemperature, high pressure condition by the compressor 201 flows by wayof of the four-way valve 213 into the condenser 203, in which itexchanges heat with air from the blower 132. In this instance, since thecondensing temperature is 40 to 60° C. or so, air passing in the duct100 is heated when it passes the condenser 203. The refrigerantcondensed in the condenser 203 is subsequently decompressed andexpanded, when it passes the capillary element 266, into mist of a lowtemperature and a low pressure. The refrigerant mist then flows into theoutside heat exchanger 202 by way of the check valve 265. The outsideheat exchanger 202 acts as an evaporator, and in the outside heatexchanger 202, the refrigerant exchanges heat with air supplied theretofrom the blower 251 so that it is evaporated. The refrigerant havingpassed the subside heat exchanger 202 can flow to both of the solenoidvalve 261 side and the capillary tube 211 side, but since thecommunication resistance is higher on the capillary tube 211 side, therefrigerant flows, as a result, into the accumulator 212 by way of thesolenoid valve 261 past the branching point 264. It is to be noted that,while the refrigerant passage is communicated with the four-way valve213 at the branching point 264, the refrigerant will not circulate intothe outside heat exchanger 202 again due to a difference in pressure.

Subsequently, a dehumidifying operation condition of the presentautomotive air conditioner will be described. In this instance, thesolenoid valve 260 is opened and the solenoid valve 261 is closed insuch a heating operation condition as described hereinabove.Consequently, refrigerant partially condensed in the outside heatexchanger 202 is decompressed at the capillary tube 211 and flows, inthis condition, into the evaporator 207. Then, in the evaporator 207,the refrigerant will be evaporated to cool air blasted thereto from theblower 132.

Accordingly, in the dehumidifying operation, air is cooled once in theevaporator 207 and then heated in the condenser 203. Consequently, whenthe air passes the evaporator 207, the saturation evaporatingtemperature drops to cause moisture in the air to be condensed andadhere to a surface of the evaporator 207. Then, since the air isre-heated in this condition when it passes the condenser 203, therelative humidity is dropped remarkably, and consequently, gooddehumidification is performed.

FIGS. 22, 23 and 24 are Mollier charts illustrating cooling operation,heating operation and dehumidifying operation, respectively, of therefrigerating cycle shown in FIG. 21. As described above, upon coolingoperation, the outside heat exchanger 202 acts as a condenser while anevaporating action is performed in the evaporator 207. On the otherhand, upon heating operation, refrigerant is condensed in the condenser203 while the outside heat exchanger 202 acts as an evaporator.

It is to be noted that the difference in evaporating pressure betweenFIGS. 22 and 23 arises from the fact that the temperature of air flowinginto the evaporator 207 upon cooling is higher than the temperature ofair flowing into the outside heat exchanger 202 upon heating.

On the other hand, as seen from FIG. 24, upon dehumidifying operation,condensation of refrigerant is performed by the condenser 203 and theoutside heat exchanger 202 while evaporation of refrigerant is performedby the evaporator 207. In this instance, the enthalpy is higher at theevaporator 207 than at the condenser 203, but since condensation ofmoisture in air proceeds in the evaporator 207, the temperature of airis not lowered very much when it passes the evaporator 207 due to latentheat involved in the condensation of water. Meanwhile, since theenthalpy of the condenser 203 is all used to raise the temperature ofair, the temperature of air having passed both of the evaporator 207 andthe condenser 203 either has a substantially same level or is raised asa result.

Subsequently, control of the temperature of air of the automotive airconditioner upon dehumidifying operation will be described. FIGS. 25, 26and 27 are Mollier charts all illustrating operating conditions upondehumidifying operation, and FIG. 25 shows a Mollier chart upon normaloperation. In the normal operation, the blower 251 is rotated weakly sothat a predetermined amount of air is blasted to the outside heatexchanger 202 to assure heat exchanging at the outside heat exchanger202. As a result, the air temperature lowering capacity of theevaporator 207 substantially coincides with the air temperature raisingcapacity of the condenser 203, and air having passed both of theevaporator 207 and the condenser 203 raises its temperature a little.

FIG. 26 shows a condition wherein it is desired to raise the blown outair temperature in dehumidifying operation. In this instance, the blower251 stops its action in order to reduce the heat exchanging capacity ofthe outside heat exchanger 202. As a result, the condensing capacity isdecreased generally while the condensing pressure is increased. As thecondensing pressure rises, the temperature of air when it passes thecondenser will be raised.

FIG. 27 shows another condition wherein it is desired to lower the blownout air temperature in dehumidifying operation. In this instance, theblower 251 for the outside heat exchanger 202 is rotated at a high speedto raise the condensing capacity of the outside heat exchanger 202. As aresult, the condensing pressure is lowered, and air cooled when itpasses the evaporator 207 will be blown out into the room of theautomobile without being heated very much.

It is to be noted that, in the case of FIG. 27, since the totalcondensing capacity of the outside heat exchanger 202 and the condenser203 is increased, the condensing pressure in the refrigerating cycle islowered, and as a result, also the evaporating pressure at theevaporator 207 is lowered. Consequently, there is the possibility thatfrost may appear on the evaporator 207. Therefore, in this instance, thespeed of rotation of the compressor 201 is controlled so thatdehumidifying operation may continuously proceed without lowering thepressure in the evaporator 207, that is, the sucking pressure of airinto the compressor 201, very much.

Subsequently, defrosting of the outside heat exchanger 202 upon heatingoperation will be described. As described hereinabove, since the outsideheat exchanger 202 functions as an evaporator in heating operation,particularly when the temperature of outside air is low, the temperatureof a surface of the outside heat exchanger 202 becomes lower than thefreezing point and frost adheres to the outside heat exchanger 202.Then, if frost adheres in this manner, the heat exchanging function ofthe outside heat exchanger 202 deteriorated remarkably so that goodoperation of one refrigerating cycle cannot be achieved and consequentlyheating operation of the condenser 203 is not performed. Thus, in thisinstance, refrigerant in a high temperature, high pressure conditionwill be passed through the outside heat exchanger 202 to melt the frostadhering to the outside heat exchanger 202. In the dehumidifyingoperation, operation of the outside blower 251 is stopped first.Meanwhile, the inside blower 132 is rotated at a low speed. Then, theinside/outside air changing over damper 131 is put into an inside airadmitting condition so that the temperature of blown out air from theduct 100 may not be lowered. Further, power is made availablesimultaneously to the auxiliary heater 700 and 701. In this condition,the solenoid valve 260 is opened while the solenoid valve 261 is closed.Consequently, refrigerant having passed the compressor 201 flows intothe condenser 203 and the outside heat exchanger 202 while it remains ina high temperature, high pressure condition. As a result, thetemperature of the outside heat exchanger 202 rises and frost adheringto the surface of the outside heat exchanger 202 will be melted. Therefrigerant condensed in the outside heat exchanger 202 is thendecompressed and expanded in the capillary tube 211 and then flows intothe evaporator 207. As a result, the temperature of air in the duct 100becomes low, but since, in this condition, the amount of a wind of theblower 132 is small and the auxiliary heaters 700 and 701 can work tothe utmost, remarkable deterioration of the blown out air temperaturecan be prevented.

Further, in order to accomplish defrosting of the outside heat exchanger202 in a short period of time, the compressor 201 has a capacity as highas possible and the invertor thereof has a frequency as high aspossible.

It is to be noted that, when defrosting operation is proceeding in thismanner, a lamp may be lit so that this may be recognized by a passengerof the automobile.

Further, when operation of the automotive air conditioner is automaticoperation, changing over between heating operation and defrostingoperation is performed in accordance with the following conditions:

(1) The temperature of the outside heat exchanger 202 is lower by 10° C.or more than the temperature of outside air:

(2) The temperature of the outside heat exchanger 202 is lower than -3°C. or so: and

(3) Heating operation has continued for longer than a predeterminedperiod of time (60 minutes).

Whether or not defrosting is required is judged in accordance with theconditions.

FIG. 28 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner adopts athree-way valve 269 in place of the four-way valve 213 of the automotiveair conditioner shown in FIG. 21. In addition, a solenoid valve 268 isdisposed in a cooling pipe adjacent the branching point on the upstreamof the accumulator 212.

Upon cooling operation, the three-way valve 269 is changed over to aposition indicated by a solid line so that refrigerant discharged fromthe compressor 201 may be introduced to the outside heat exchanger 202.In this instance, the outside heat exchanger 202 acts as a condenser,and refrigerant decompressed and expanded in the capillary tube 211 isthen supplied to the evaporator 207. The refrigerant evaporated in theevaporator 207 is fed back to the accumulator 212 side past thebranching point 264. The solenoid valve 268 opens the refrigerant pipeupon cooling operation. Consequently, also refrigerant accumulated inthe condenser 203 is supplied, due to sucking action of the compressor201, from the refrigerant pipe to the compressor 201 side by way of thesolenoid valve 268 and the branching point 264. In this instance, thepressure of refrigerant in the condenser 203 is decreased suddenly sothat also the evaporating temperature of the refrigerant is lowered.Consequently, immediately after starting of cooling operation, alsorefrigerant accumulated in the condenser 203 is evaporated thereby tocomplement the cooling capacity. On the other hand, upon heatingoperation, the three-way valve 269 is changed over so that refrigerantdischarged from the compressor 201 is now introduced into the condenser203. Further, the solenoid valve 260 is closed so that refrigerantcondensed in the condenser 203 is supplied to the outside heat exchanger202 by way of the capillary element 266. Meanwhile, the solenoid valve261 is opened so that refrigerant evaporated in the outside heatexchanger 202 is sucked from the solenoid valve 261 toward theaccumulator 212 side. In this instance, the solenoid valve 268 is in aclosed condition, and refrigerant discharged from the compressor 201 isprevented from being short-circuited to be sucked to the accumulator 212side.

Upon dehumidifying operation, the three-way valve 296 introducesrefrigerant discharged from the compressor 201 to the condenser 203.Meanwhile, the solenoid valve 260 opens the refrigerant passage so thatrefrigerant of a high pressure is supplied from the condenser 203 to theoutside heat exchanger 202. Then, the solenoid valve 261 is closed sothat refrigerant condensed by the condenser 203 and the outside heatexchanger 202 is supplied to the evaporator 207 by way of the capillarytube 211.

It is to be noted that actions in defrosting operation and dehumidifyingoperation of the automotive air conditioner of FIG. 28 are similar tothose of the automotive air conditioner shown in FIG. 21.

FIG. 29 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner employs a pairof solenoid valves 270 and 271 in place of the three-way valve 269 ofthe automotive air conditioner of FIG. 28. Actions in cooling operation,heating operation and dehumidifying operation are similar to those ofthe automotive air conditioner of FIG. 28.

FIG. 30 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner employs asingle three-way valve 272 in place of the two solenoid valves 270 and268 of the automotive air conditioner of FIG. 29.

FIG. 31 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner is constructedsuch that the operation thereof between cooling operation and heatingoperation is performed by changing over of the four-way valve 213.

In particular, upon cooling operation, the four-way valve 213 introduceshigh pressure refrigerant discharged from the compressor 201 into theoutside heat exchanger 202. The refrigerant condensed in the outsideheat exchanger 202 is decompressed and expanded in the capillary tube211 and supplied to the evaporator 207. It is to be noted that a backflow of the refrigerant to the condenser 203 side then is prevented by acheck valve 273. Then, the refrigerant evaporated in the evaporator 207is sucked into the compressor 201 by way of the accumulator 212.

On the other hand, upon heating, the four-way as changed over so thatrefrigerant discharged from the compressor 201 is supplied to thecondenser 203. Then, the refrigerant condensed in the condenser 203 isdecompressed and expanded when it passes the capillary element 266, andafter then, it flows to the branching point 274 by way of the checkvalve 273. Most of the refrigerant coming to the branching point 274flows to the outside heat exchanger 202 side due to a difference inpressure. Meanwhile, part of the refrigerant flows to the evaporator 207by way of the capillary tube 211. Then, the refrigerant evaporated inthe outside heat exchanger 202 and the evaporator 207 is supplied to theaccumulator 213 and then fed back to the compressor 201.

In such heating operation, refrigerant will not flow much to theevaporator 207 side due to a resistance of the capillary tube 211.However, some refrigerant is supplied to the evaporator 207, at whichpart of the refrigerant is evaporated. Consequently, even duringheating, some dehumidifying operation is achieved.

FIG. 32 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, changingover of a cycle is performed by the single four-way valve 213 and asingle on/off soienoid valve 290. Upon cooling operation, the four-wayvalve 213 is changed over to a position indicated by a solid line inFIG. 32 and the solenoid valve 290 is opened. As a result, refrigerantdischarged from the compressor 201 is condensed in the outside heatexchanger 202 and then decompressed and expanded in the capillary tube211, whereafter it flows into the evaporator 207. Then, the refrigerantcools air by an evaporating action of the evaporator 207. On the otherhand, upon heating, the four-way valve 213 is changed over to anotherposition indicated by a broken line in FIG. 32, and also the solenoidvalve 290 is put into an open condition. As a result, refrigerantdischarged from the compressor 201 is condensed in the condenser 203 andthen decompressed and expanded in the capillary 266. After then, therefrigerant passes the check valve 273 and then flows mainly to theoutside heat exchanger 202 side due to a difference in pressure.Meanwhile, part of the refrigerant flows into the evaporator 207 by wayof the capillary tube 211. Then, the refrigerant having passed theoutside heat exchanger 202 and the evaporator 207 is collected into theaccumulator 212 and then fed back into the compressor 201. In thiscondition, since some refrigerant flows into the evaporator 207,dehumidifying operation is performed suitably upon heating.

Further, when dehumidifying operation is to be performed, the four-wayvalve 213 is changed over similarly as upon heating operation describedabove, and the solenoid valve 290 is opened and closed at suitabletimings. When the solenoid valve 290 closes the refrigerant passage,refrigerant flows into the evaporator 207 by way of the capillary tube211 so that the cooling capacity of the evaporator 207 is increased.Consequently, the dehumidifying function of the evaporator 207 isincreased. Then, a required dehumidifying amount is obtained by suitablychanging over the opening/closing operation of the solenoid valve 290 ata suitable duty ratio. Upon dehumidifying operation, the solenoid valve290 may be held closed normally.

FIG. 33 shows a yet further automotive air conditioner according to thepresent invention. Upon cooling operation, the four-way valve 213 ischanged over to a position indicated by a solid line in FIG. 33 and thesolenoid valve 293 opens its refrigerant pipe while the solenoid valve294 closes its refrigerant pipe. Meanwhile, the solenoid valve 291 opensits refrigerant pipe. It is to be noted that the solenoid valve 292performs opening and closing operations of the refrigerant pipe suitablyin accordance with a required cooling capacity. Accordingly, in thiscondition, refrigerant discharged from the compressor 201 flows into theoutside heat exchanger 202 by way of the four-way valve 213 and thesolenoid valve 293 and is condensed in the outside heat exchanger 202.After then, the refrigerant passes the solenoid valve 291 and isdecompressed and expanded in the capillary tube 211, whereafter it isevaporated in the evaporator 207. After then, it passes the accumulator212 and is fed back to the compressor 201.

Upon heating operation, the four-way valve 213 is changed over toanother position indicated by a broken line in FIG. 33 and the solenoidvalve 291 closes its refrigerant pipe. Meanwhile, the solenoid valve 292opens its refrigerant pipe: the solenoid valve 293 opens its refrigerantpipe: and the solenoid valve 294 closes its refrigerant pipe. As aresult, refrigerant discharged from the compressor 201 flows into thecondenser 203 by way of the four-way valve 213 and is then decompressedand expanded in the capillary element 266, whereafter it is evaporatedin the outside heat exchanger 202. After then, it is fed back to thecompressor 201 by way of the solenoid valve 293, the four-way valve 213and the accumulator 212.

Subsequently, dehumidifying operation will be described. In thisinstance, both of the solenoid valves 291 and 294 are opened. As aresult, refrigerant discharged from the compressor 201 is divided into aflow which then is liquefied in the condenser 203 and flows to theevaporator 207 by way of the capillary 211 and another flow which thenflows by way of the solenoid valve 294 into the outside heat exchanger202, in which it is liquefied, whereafter it flows to the evaporator 207by way of the solenoid valve 291 and the capillary tube 211. Inparticular, condensation of refrigerant is performed in parallel by thecondenser 203 and the outside heat exchanger 202. Then, the refrigerantevaporated in the evaporator 207 flows into the accumulator 212 by wayof the refrigerant pipe.

Here, upon such dehumidifying operation, the condensing pressure can becontrolled by varying the heat exchanging capacity of the outside heatexchanger 202. The capacity control of the outside heat exchanger 202 isperformed by varying the amount of blown out air by the blower 251.Alternatively, a damper for the outside heat exchanger 202 may beprovided in place of the blower 251. Further, the opening and closingtimes of the solenoid valve 294 may be controlled to control thecondensing pressure, that is, the blown out air temperature.

FIG. 34 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, coolingoperation, heating operation and dehumidifying operation are selectivelyperformed by suitably changing over solenoid valves 295, 296 and 297.First, cooling operation will be described. In this instance, thesolenoid valve 295 closes its refrigerant passage while the solenoidvalve 296 opens its refrigerant passage and also the solenoid valve 297opens its refrigerant passage. Further, the four-way valve 213 ischanged over to a position indicated by a broken line. Consequently,refrigerant discharged from the compressor 201 flows by way of thefour-way valve 213 into the outside heat exchanger 202, in which itexchanges heat with outside air so that it is condensed. The refrigerantthen flows into the solenoid valve 296 by way of the check valve 280 andthen passes the capillary element 266, whereupon it is decompressed andexpanded. After then, the refrigerant flows into the evaporator 207, inwhich it takes heat of vaporization away from air so that is itevaporated. After then, the refrigerant flows into the accumulator 212by way of the solenoid valve 297 and the four-way valve 213.

On the other hand, upon heating, the solenoid valve 295 opens itsrefrigerant pipe while the solenoid valve 296 closes its refrigerantpipe and also the solenoid valve 297 closes its refrigerant pipe.Further, the four-way valve 213 is changed over to another positionindicated by a solid line in FIG. 34. Consequently, upon heatingoperation, refrigerant discharged from the compressor 201 successivelypasses the four-way valve 213, the check valve 281 and the solenoidvalve 295 and is then condensed in the condenser 203. After then, therefrigerant is decompressed and expanded when it passes the capillarytube 211, and then flows into the outside heat exchanger 202 by way ofthe check valve 282. Then, the refrigerant is evaporated in the outsideheat exchanger 202 and is fed back into the compressor 201 by way of thefour-way valve 213 and the accumulator 212.

Subsequently, dehumidifying operation will be described. In thisinstance, the solenoid valve 295 is opened while the solenoid valve 296is closed and also the solenoid valve 297 is closed. Then, the four-wayvalve 213 is changed over to the position indicated by the broken linein FIG. 34. Accordingly, refrigerant discharged from the compressor 201flows by way of the four-way valve 213 into the outside heat exchanger202, in which it is condensed. Further, the refrigerant flows by way ofthe check valve 280 and the solenoid valve 295 into the compressor 203,in which it is condensed. Then, when the refrigerant passes thecapillary tube 211, it is decompressed and expanded into a lowtemperature, low pressure condition and then flows, in this condition,into the evaporator 207. The refrigerant is evaporated in the evaporator207 and then fed back into the compressor 201 by way of the solenoidvalve 297, the four-way valve 313 and the accumulator 212. Accordingly,in the automotive air conditioner shown in FIG. 34, upon dehumidifyingoperation, condensation of refrigerant is performed by the outside heatexchanger 202 and the condenser 203, and the blown out air temperatureis controlled by controlling the amount of blown out air by the blower251 to control the heat exchanging capacity of the outside heatexchanger 202 to vary the condensing pressure of the condenser 203.

In particular, in the automotive air conditioner shown in FIG. 34, upondehumidifying operation, refrigerant flows first into the outside heatexchanger 202 and then into the condenser 203. On the other hand, in theautomotive air conditioner shown in FIG. 21. refrigerant flows firstinto the condenser 203 and then into the outside heat exchanger 202.Here, in case refrigerant flows first into the condenser 203, therefrigerant having high superheat immediately after discharged from thecompressor 201 flows into the condenser 203, and consequently, the blownout air temperature from the condenser 203 becomes higher anddehumidification having some heating effect can be performed.

FIG. 35 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, theoperation is changed over among cooling operation, heating operation anddehumidifying,operation by means of the four-way valve 213 and asolenoid valve 298.

First, in cooling operation, the four-way valve 213 is changed over to aposition indicated by a broken line in FIG. 35, and the solenoid valve298 opens its passage. As a result, refrigerant discharged from thecompressor 231 flows by way of the four-way valve 213 into the outsideheat exchanger 202, in which it is condensed. Then, the condensedrefrigerant passes the check valve 283 and the solenoid valve 298 and isthen decompressed and expanded in the capillary tube 211. After then,the refrigerant is evaporated in the evaporator 207 and is fed back intothe compressor 201 by way of the accumulator 212.

On the other hand, upon heating operation, the four-way valve 213 ischanged over to another position indicated by a solid line in FIG. 35,and the solenoid valve 298 closes its refrigerant pipe. Accordingly,refrigerant discharged from the compressor 201 flows by way of thefour-way valve 213 into the condenser 203, in which it is condensed.After then, the refrigerant flows by way of the check valve 294 into thecapillary element 266, in which it is decompressed and expanded,whereafter it flows into the outside heat exchanger 202. Then, therefrigerant is evaporated in the outside heat exchanger 202 and then isfed back into the compressor 201 by way of the four-way valve 213 andthe accumulator 212.

Upon dehumidifying operation, the four-way valve 213 is changed oversimilarly to the position indicated by the solid line in FIG. 35, andthe solenoid valve 298 opens its refrigerant pipe. Consequently,refrigerant discharged from the compressor 201 flows into the condenser203, in which it is condensed and liquefied. The refrigerant liquefiedin the condenser 203 is then divided into a flow which flows into theoutside heat exchanger 202 by way of the capillary 266 and another flowwhich flows into the evaporator 207 by way of the solenoid valve 298 andthe capillary tube 211. Thus, the refrigerant is evaporated in theoutside heat exchanger 202 and the evaporator 207. The thus evaporatedrefrigerant is collected into the accumulator 212 again and is then fedback into the compressor 201. In this manner, upon dehumidifyingoperation, refrigerant flows in parallel through the outside heatexchanger 202 and the evaporator 207, and control of the dehumidifyingcapacity then is achieved by controlling the blower 251 to vary the heatexchanging capacity of the outside heat exchanger 202.

FIG. 36 shows a yet further automotive air conditioner according to thepresent invention. The present automotive air conditioner is amodification to the automotive air conditioner shown in FIG. 35 in thatit additionally includes a refrigerant pipe which interconnects, upondehumidifying operation, the downstream of the outside heat exchanger202 and the evaporator 207 and further includes a solenoid valve 299 andanother solenoid valve 289 for controlling flows of refrigerant.Operations upon cooling operation and heating operation are similar tothose of the refrigerating cycle described hereinabove with reference toFIG. 35. Upon dehumidifying operation, the solenoid valve 299 is openedwhile the solenoid valve 289 is closed, and in this instance,refrigerant is evaporated in both of the outside heat exchanger 202 andthe evaporator 207 similarly as in the refrigerating cycle shown in FIG.35. However, in case, upon dehumidifying operation, the solenoid valve298 is closed and also the solenoid valve 299 is closed while thesolenoid valve 289 is opened, refrigerant flows in series through theoutside heat exchanger 202 and the evaporator 207. In particular, inthis condition, refrigerant discharged from the compressor 201 flows byway of the four-way valve 213 into the condenser 203, in which it iscondensed. The thus condensed refrigerant flows by way of the checkvalve 284 into the capillary element 266, in which it is decompressedand expanded, whereafter it is evaporated in the outside heat exchanger202. After then, the refrigerant flows by way of the solenoid valve 289into the evaporator 207, in which it is evaporated similarly. Then, thethus evaporated refrigerant is fed back into the compressor 201 again byway of the accumulator 212. In this manner, the cycle shown in FIG. 36can be changed over, upon dehumidifying operation, between a conditionwherein refrigerant condensed by the condenser 203 is admitted inparallel into both of the evaporator 207 and the outside heat exchanger202 and another condition wherein the outside heat exchanger 202 and theevaporator 207 are disposed in series so that refrigerant is evaporatedin both of them.

FIG. 37 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, theevaporator 207 and the outside heat exchanger 202 are also disposed inseries upon dehumidifying operation, but the order in arrangement ofthem is reverse to that in the automotive air conditioner shown in FIG.36. In particular, while, in the refrigerating cycle shown in FIG. 36,the outside heat exchanger 202 and the evaporator 207 are connected inseries upon dehumidifying operation such that the outside heat exchanger202 may be positioned on the upstream side, in the refrigerating cycleshown in FIG. 37, the evaporator 207 and the outside heat exchanger 202are connected such that the evaporator 207 may be positioned on theupstream side of the outside heat exchanger 202.

Subsequently, the refrigerating cycle shown in FIG. 37 will bedescribed. First, upon cooling operation, the four-way valve 213 ischanged over to a position indicated by a broken line in FIG. 37, andthe solenoid valve 288 closes its refrigerant passage while the solenoidvalve 298 opens its refrigerant passage. Accordingly, refrigerantdischarged from the compressor 201 flows by way of the four-way valve213 into the outside heat exchanger 202, in which it is condensed. Thethus liquefied refrigerant flows through the check valve 213 and thesolenoid valve 298 into the capillary tube 211, and it is decompressedand expanded when it passes the capillary tube 211. Then, therefrigerant is evaporated in the evaporator 207 and then flows into theaccumulator 212 by way of the four-way valve 213, whereafter it is fedback into the compressor 201.

On the other hand, upon heating operation, the four-way valve 213 ischanged over to another position indicated by a solid line in FIG. 37,and the solenoid valve 288 is opened while the solenoid valve 298 isclosed. Accordingly, in this condition, refrigerant discharged from thecompressor 201 flows into the condenser 203 by way of the four-way valve213. Then, the refrigerant condensed in the condenser 203 flows into thecapillary element 266 by way of the solenoid valve 288 and isdecompressed and expanded when it passes the capillary element 266.After then, the refrigerant is evaporated in the outside heat exchanger202, and then the thus evaporated refrigerant flows into the accumulator212 by way of the four-way valve 213, whereafter it is fed back to thecompressor 201 again.

Further, upon dehumidifying operation, the four-way valve 213 is changedover to the position indicated by the solid line in FIG. 37 and thesolenoid valve 298 is opened while the solenoid valve 288 is closed.Accordingly, refrigerant discharged from the compressor 201 flowsthrough the four-way valve 213 into the condenser 203, in which it iscondensed and liquefied. After then, the refrigerant flows through thesolenoid valve 298 into the capillary tube 211 and is decompressed andexpanded when it passes the capillary tube 211. After then, therefrigerant flows into the evaporator 207, in which it is evaporated.After then, the refrigerant flows through the check valve 286 into theoutside heat exchanger 202, in which it is further evaporated. Then, therefrigerant is fed back into the compressor 201 by way of the four-wayvalve 213 and the accumulator 212. Accordingly, upon such dehumidifyingoperation, refrigerant is evaporated in both of the evaporator 207 andthe outside heat exchanger 202, and besides the evaporator 207 islocated on the upstream side of the outside heat exchanger 202.

Here, it is suitably selected in accordance with the necessity, when theoutside heat exchanger 202 and the evaporator 207 are disposed in seriesupon dehumidifying operation, which one of them is located on theupstream side. However, in a cycle which includes the accumulator 212,there is no significant difference in function whichever one of them isdisposed on the upstream side. In particular, since the outside heatexchanger 202 and the evaporator 207 do not present differentevaporating pressures while the temperatures of air admitted into themare different from each other, the evaporating capacity of theevaporator 207 is equal whether it is located on the upstream side or onthe downstream side.

FIG. 38 shows a yet further automatic air conditioner according to thepresent invention. In, the present automotive air conditioner, theevaporator 207 includes a damper 159 having a variable capacity. Uponcooling operation and upon dehumidifying operation, the damper 159 opensthe duct 100 so that air may be admitted into the evaporator 207, butupon heating operation, the damper 159 is closed so that air may not beadmitted into the evaporator 207. Meanwhile, a flow of refrigerant tothe condenser 203 is changed over by the three-way valve 213 and thesolenoid valve such that refrigerant may be condensed, upon heatingoperation and upon dehumidifying operation, in the condenser 203, butrefrigerant may flow, upon cooling operation, directly to the outsideheat exchanger 202 bypassing the condenser 203.

FIG. 39 shows a yet further automatic air conditioner according to thepresent invention. While a flow of refrigerant is changed over, in theautomatic air conditioner shown in FIG. 38, between the condenser 203side and the other side bypassing the condenser 203, in the automaticair conditioner shown in FIG. 39, the capacity of the condenser 203 ischanged over by means of the damper 154. In particular, upondehumidifying operation and upon heating, the damper 154 opens the duct100 so that air may be admitted into the condenser 203, but upon coolingoperation, the damper 154 is closed so that air may not be admitted intothe condenser 203. However, even during cooling operation, when thedamper 154 operates as an air mixing damper for varying the blown outair temperature, the damper 154 opens its passage in response to anecessary blown out a air temperature so that part of air may bere-heated.

FIG. 40 shows a yet further automatic air conditioner according to thepresent invention. The present automatic air conditioner includes,similarly to the automatic air conditioner described hereinabove withreference to FIG. 13, the dampers 154 and 159 for both of the condenser203 and the evaporator 207, respectively. However, the present automaticair conditioner is different in circuit of the refrigerating cycle fromthe automatic air conditioner shown in FIG. 13. A flow of refrigerant iscontrolled in the refrigerating cycle by changing over of the solenoidvalves 260 and 261. Upon heating operation, the solenoid valve 260 isopened while the solenoid valve 261 is closed. Consequently, refrigerantdischarged from the compressor 201 flows through the condenser 203 andthe solenoid valve 260 into the outside heat exchanger 202, in which itis evaporated. It is to be noted that, in this instance, the condenser203 does not perform a condensing action in principle as the damper 154is held closed. Then, the refrigerant condensed in the outside heatexchanger 202 is decompressed and expanded when it passes the capillarytube 211, and consequently, the refrigerant in a low temperature, lowpressure condition flows into the evaporator 207. In this condition, thedamper 159 holds the duct 100 in a closed condition, and consequently,air from the blower 132 flows into the evaporator 207 to evaporate therefrigerant. The thus evaporated refrigerant is then fed back into thecompressor 201 by way of the accumulator 212.

On the other hand, upon heating operation, the solenoid valve 260 isclosed while the solenoid valve 261 is opened. In this condition,refrigerant discharged from the compressor 201 flows into the condenser203, in which it is condensed. In particular, in this condition, thedamper 154 is opened so that air may be admitted into the condenser 203.After then, the refrigerant is decompressed and expanded when it passesthe capillary element 266, and is then evaporated in the outside heatexchanger 202. The thus evaporated refrigerant is fed back into thecompressor 201 by way of the solenoid valve 261 and the evaporator 207.In this condition, the evaporator 207 is closed by the damper 159, andconsequently, refrigerant is little evaporated in the evaporator 207.

Subsequently, upon dehumidifying operation, the solenoid valve 260 isopened while the solenoid valve 261 is closed. Accordingly, refrigerantdischarged from the compressor 201 flows into the condenser 203, inwhich it is condensed. The refrigerant then flows through the solenoidvalve 260 into the outside heat exchanger 202, also which accomplishes acondensing function to condense the refrigerant. After then, therefrigerant is decompressed and expanded when it passes the capillarytube 211, and is then evaporated in the evaporator 207. Then, therefrigerant thus evaporated in the evaporator 207 is fed back to thecompressor 201 by way of the accumulator 212. In this condition, theevaporating capacity of the evaporator 207 and the condensing capacityof the condenser 203 are variably controlled by adjusting the circuitsof the dampers 159 and 154, respectively. Further, in order to controlthe condensing capacity of the condenser 203, the condensing capacitycontrol of the outside heat exchanger 202 by control of the amount ofair of the fan 151 for the outside heat exchanger 202 or the like may beemployed additionally similarly as in the case of the automotive airconditioner shown in FIG. 21.

As described so far, with the automotive air conditioner of the presentinvention, the operation can be changed over among cooling operation,heating operation and dehumidifying operation by controlling the routesof flows of refrigerant through the compressor 201, the outside heatexchanger 202, the condenser 203, the evaporator 207 and thedecompressing or expanding means 211. Further, according to the presentinvention, further advantageous air conditioning operation describedbelow can be achieved by suitably controlling changing over particularlybetween a dehumidifying operation condition and a heating operationcondition.

In case fogging of the windshield of the automobile is forecast ordetected in a heating operation condition, the condition of thewindshield can be prevented well by changing over the flow ofrefrigerant into that of a dehumidifying operation condition.Particularly upon dehumidifying operation, since the drop in temperatureof blown out air at the evaporator 207 is greater than the rise at thecondenser 203 as described above, dehumidification having somewhatheating effect can be achieved. Accordingly, even if the operation ischanged over from a heating operation condition to a humidifyingoperation condition, the temperature of blown out air will not belowered remarkably, and consequently, good heating can be achieved.

Meanwhile, in a humidifying operation condition, since the evaporator207 performs an evaporating action, particularly when the temperature ofair sucked into the evaporator 207 is low as in winter, there is thepossibility that the evaporator 207 may be frozen. Thus, in such a case,otherwise possible freezing of the evaporator 207 can be prevented wellby changing over the operation from the dehumidifying operation to aheating operation.

FIG. 41 shows a flow chart when the operation is changed over from aheating operation condition to a dehumidifying operation condition. Thepresent flow chart is used to control changing over of the solenoidvalves of the refrigerating cycle described hereinabove. After operationis started at step 440, it is judged at step 441 whether or not the airconditioner switch 305 is on or off. In case the air conditioner switch305 is on, it is then judged at step 442 whether or not therefrigerating cycle is in an operation condition wherein it blows outonly a weak wind or in an air conditioning operation condition whereinthe compressor 201 is operating. If an air conditioning operationcondition is judged at step 442, judgment of a cooling operationcondition, a dehumidifying operation or a heating operation condition isperformed at step 443.

As described hereinabove, in any of the refrigerating cycles, in acooling operation condition, refrigerant discharged from the compressor201 is condensed in the outside heat exchanger 202, and thendecompressed and expanded, whereafter it is supplied into the evaporator207. Then, the refrigerant takes heat of vaporization away from air inthe evaporator 207 to cool the air. On the other hand, in a heatingoperation condition, refrigerant discharged from the compressor 201flows into the condenser 203, in which it radiates heat of condensationinto air to heat the air. After then, the refrigerant is decompressedand expanded, and then it is evaporated in the outside heat exchanger202 and fed back into the compressor 201 again. Upon dehumidifyingoperation, the manner of use of the outside heat exchanger 202 isdifferent among the different refrigerating cycles, but the condenser203 performs a condensing function to radiate heat of condensation intoair to heat the air. Further, the evaporator 207 performs an evaporatingaction to cool air by heat of vaporization to condense moisture fromwithin the air. Then, the outside heat exchanger 202 acts as anevaporator or a condenser depending upon a circuit of the refrigeratingcycle. Further, as described already, a flow of refrigerant flowing tothe outside heat exchanger 202 may flow in series to the condenser 203or in parallel to the condenser 203. In particular, in a firstcondition, refrigerant discharged from the compressor 201 first flowsinto the condenser 203 and then into the outside heat exchanger 202 sothat it may undergo a condensing action by both of condenser 203 and theoutside heat exchanger 202, whereafter it flows into the evaporator 207by way of the capillary tube 211. On the other hand, in a secondcondition, refrigerant discharged from the compressor 201 is supplied inparallel into both of the condenser 203 and the outside heat exchanger202, and then the refrigerant condensed in both of the condenser 203 andthe outside heat exchanger 202 is supplied into the evaporator 207 byway of the capillary tube 211.

Further, also wren the outside heat exchanger 202 acts as an evaporatorupon dehumidifying operation, similarly two cases are availableincluding a first case wherein refrigerant flows in series and a secondcase wherein refrigerant flows in parallel. In particular, in the firstcase, refrigerant condensed in the condenser 203 flows, after passingthe capillary tube 212, in series through the outside heat exchanger 202and the evaporator 207 such that an evaporating action is achieved byboth of the outside heat exchanger 202 and the evaporator 207,whereafter the refrigerant is sucked into the compressor 201.Particularly in this instance, either the evaporator 207 may be locatedon the upstream side of the outside heat exchanger 202 or the outsideheat exchanger 202 may be located on the upstream side of the evaporator207.

Meanwhile, in the second case, liquid refrigerant condensed in thecondenser 203 is supplied, after passing the capillary tube 211, inparallel to both of the outside heat exchanger 202 and the evaporator207.

In the present flow chart of FIG. 41, it is judged, at step 444, inaccordance with a changed over condition of the inside/outside airchanging over damper 131 whether a heating operation or a dehumidifyingoperation should be performed in a heating operation condition. Then, incase an outside air admitting condition is detected at step 444, theheating operation condition is maintained. This is because, normally inan outside air introducing condition, ventilation of the room of theautomobile is performed and the windshield is not likely fogged.

In case it is judged at step 444 that the inside/outside air changingover damper 131 is in an inside air admitting condition, it is judgedsubsequently at step 445 whether or not a cancelling switch is on oroff.

The cancelling switch is provided, though not shown, on the controlpanel for preventing, by manual operation thereof, operation of theautomatic air conditioner from automatically changing over from aheating operation condition to dehumidifying operation. However, in casethe cancelling switch is on, even if it is forecast at step 444 that thewindshield may be fogged, heating operation will still be continued.

Only when the cancelling switch is not on, dehumidifying operation isperformed in case fogging of the windshield is forecast at step 444.Preferably, the dehumidifying operation here is dehumidifying operationhaving some heating effect. This is achieved by lowering, in therefrigerating cycle in which the outside heat exchanger acts as acondenser, the heat exchanging function of the outside heat exchanger.It is to be noted that such dehumidifying operation having some heatingeffect will be hereinafter described.

It is to be noted that, while, in the flow chart of FIG. 41, a foggedcondition of the windshield is judged in accordance with a changing overcondition of the inside/outside changing over damper 131, changing overmay otherwise be performed in accordance with a blowing out mode or anoutside air condition as seen from the flow chart shown in FIG. 42.

In particular, even if an outside air admitting condition is detected atstep 444, if it is judged at step 446 that air flows to the def spithole 146, then it is determined that the passenger requiresdehumidification, and consequently, the operation is changed over to thedehumidifying operation side. It is to be noted that judgment of a modeat step 444 and judgment of changing over between spit holes at step 446are different from each other as described subsequently In particular,the judgment of a mode at step 444 is made principally based on anecessary blown out air temperature Tao while changing over of a mode atstep 446 is performed by selection of the passenger.

At step 447, it is judged whether or not the temperature of outside airis equal to or higher than 0° C. Here, in case it is judged that theoutside air temperature is lower than 0° C. heating operation isselected because, otherwise if dehumidifying operation is performed,then there is the possibility that the evaporator 207 may be frozen.Then, when the outside air temperature is equal to or higher than 0° C.and there is no possibility that the evaporator 207 may be frozen,dehumidifying operation is selected.

The DEF mode at step 446 mentioned above denotes a condition wherein airflows to the def spit hole 146 and includes not only a case wherein theentire amount of air flows to the def spit hole 146 but also anothercase wherein air flows to both of the def spit hole 146 and the footspit hole 145.

FIG. 43 shows another flow chart of changing over between heatingoperation and dehumidifying operation. In the flow chart of FIG. 43,fogging of the windshield is judged at step 448. The judgment isperformed using a dewing sensor not shown. The dewing sensor identifiesfrom a temperature of a glass portion and a humidity of air whether ornot the surface of the glass is lower than a dew point of moisture inthe air in order to forecast occurrence of fogging. Then, in caseoccurrence of fogging is not detected or forecast at step 448, theautomotive air conditioner enters heating operation.

In case occurrence of fogging is forecast at step 448, a temperature ofoutside air is detected at step 447, and if the outside air temperatureis equal to or higher than 0° C., then dehumidifying operation havingsome heating effect is selected. In this instance, the inside/outsideair changing over damper is put into an inside air admitting conditionin order to achieve a high heating efficiency while the damper 141 isopened so that warm air may advance from the def spit hole 146 towardthe windshield.

In case a temperature of outside air equal to or higher than 0° C. isdetected at step 447, heating operation is selected in order to preventfreezing of the evaporator 207. However, since this condition is acondition wherein fogging of the windshield is forecast, theinside/outside air changing over damper 131 is put into the outside airadmitting condition. Further, the damper 141 opens the def passage 146so that air warmed by heating operation may be blown out from the defspit hole 146 toward the windshield.

In case it is judged at step 447 that the outside air temperature isequal to or higher than 0° C. dehumidifying operation having someheating effect is performed. In this instance, the inside/outside airchanging over damper 131 is changed over to the inside air admittingcondition in order to lower the heating load. Further, the def spit hole146 is opened so that fogging of the windshield may be prevented well.

FIG. 44 is a flow chart illustrating a further control for theprevention of fogging of the windshield. In the present flow chart,detection of occurrence of fogging is executed in accordance with theposition of the inside/outside air changing over damper 131 (step 444).Then, in case an inside air admitting condition is judged at step 444,since this is a condition wherein fogging of the windshield is forecast,an actual situation of the windshield is judged at step 448. Then, incase it is detected that the windshield is actually fogged or isentering into a fogged condition, dehumidifying operation having someheating effect is selected. On the contrary if fogging of the windshieldis not detected at step 448, even if an inside air admitting conditionis judged at step 444, heating operation will be continued.

FIG. 45 shows a flow chart of another example of controlling changingover between dehumidifying operation having some heating effect andheating operation. In the present example, a changed over position ofthe inside/outside air changing over damper 131 is judged at step 444and the changing over is controlled in accordance with the judgmentsimilarly as in the flow chart described hereinabove. However, even whenan inside air admitting condition is detected at step 444, when thecancelling switch is in an on-state, heating operation is continued(step 445) similarly as in the flow chart shown in FIG. 42. Further, inthe flow chart shown in FIG. 45, a step 449 is added so that an elapsedtime after the inside/outside changing over damper 131 has been changedover to the inside air admitting condition may be judged. This isbecause, even if the inside/outside air changing over damper 131 ischanged over to the inside air admitting condition, this will notimmediately result in fogging of the windshield. Thus, in case it isjudged at step 449 that the inside air admitting condition has continuedfor a predetermined period of time, for example, for 1 to 3 minutes orso, dehumidifying operation having some heating effect is entered.

On the other hand, in case it is detected at step 449 that the insideair admitting condition has continued but for a period of time shorterthan the predetermined period of time, for example, 1 to 3 minutes,heating operation will be continued. This is because, depending upon adriving condition of the automobile, the automotive air conditioner issometimes used in such a manner that the admitting time of inside aircomes to an end after a comparatively short period of time such that theinside air admitting condition may be entered and continued only whilethe automobile is driving, for example, in a tunnel.

It is to be noted that, while, in the flow chart shown in FIG. 45,dehumidifying operation having some heating effect is performed ifdehumidification is necessary when heating operation is selected at step443, alternatively dehumidifying operation having some heating effectand heating operation may be performed alternately as seen from FIG. 46.In this instance, such alternate operation may be performed at intervalsof 5 to 10 minutes or so. Consequently, even upon dehumidifyingoperation, heating of the room of the automobile can be performed well.

A flow chart of control wherein, when dehumidifying operation isselected at step 443, the operation is changed over to heating operationis shown in FIG. 47.

This is because, since the evaporator 207 operates, in a dehumidifyingoperation condition, so that cool air is normally admitted into theevaporator 207 from outside the automobile as described above, there isthe possibility that the evaporator 207 may be frozen. If the evaporator207 is frozen, then the ventilation resistance is increased and the heatexchanging efficiency is deteriorated.

Therefore, in the flow chart of FIG. 47, a frozen condition of theevaporator 207 is judged at step 450. The judgment at step 450determines a frozen condition of the evaporator 207 when the detectiontemperature signal from the temperature sensor for detecting atemperature of the surface of the evaporator 207 is lower than 0° C. andthe temperature of air having passed the evaporator 207 is lowered to 0°C. or so.

If a frozen condition of the evaporator 207 is not determined at step450, dehumidifying operation is performed. However, when a frozencondition of the evaporator 207 is detected at step 450, the controlsequence advances to step 451. At step 451, it is judged whether or notthe room temperature is equal to or higher than a preset temperature.Then, if a condition wherein the room temperature is equal to or higherthan the preset temperature is determined at step 451, then this is acondition wherein no heating is required for the room of the automobile.Accordingly, in this instance, the operation is not changed over toheating operation. However, since a frozen condition of the evaporator207 has been determined at step 450, the discharging capacity of theevaporator 201 is lowered in order to cancel the frozen condition.Consequently, the evaporating capacity of the evaporator 207 is loweredso that at least freezing at the evaporator 207 may not proceed anymore.

If a condition wherein the room temperature is lower than the presettemperature is determined at step 451, then since heating operation willnot cause the passenger to have a disagreeable feeling in thiscondition, the operation is changed over to heating operation.

It is to be noted that it is naturally possible to eliminate the step451 in the control flow chart of FIG. 45, In other words, the operationmay be changed over to heating operation if freezing at the evaporator207 is detected at step 450.

Subsequently, control when a frosted condition of the outside heatexchanger 202 is detected in a heating operation condition and theoperation is changed over to dehumidifying operation will be described.Referring to the flow chart of FIG. 48, when a heating mode is selectedat step 443, a frosted condition of the outside heat exchanger 202 isdetected at subsequent step 452.

This is because, since the outside heat exchanger 202 operates as anevaporator in a heating operation condition as described hereinabove,there is the possibility that frost may appear on the surface of theoutside heat exchanger 202 when the temperature of of outside air islow. The judgment at step 452 is performed in the following conditions.First, it is judged whether or not the heating operation time in acondition wherein the temperature of the outside heat exchanger 202 islower then -3° C. has continued for more than one hour, and then it isjudged whether or not the temperature of the outside heat exchanger 202is lower by 12° C. or more than the temperature of outside air When thetemperature of the outside heat exchanger 202 is not lower than -3° C.,this indicates that the temperature of the surface of the outside heatexchanger 202 is not so low as will lead to frosting, and when thetemperature of the outside heat exchanger 202 is not lower by 12° C. ormore than the temperature of outside air, this indicates that asufficient evaporating function is assured with the outside heatexchanger 202. In other words, if frost appears on the surface of theoutside heat exchanger 202, then passage of heat is obstructed, and as aresult, the evaporating action of the outside heat exchanger 202 isdeteriorated. Therefore, the evaporating pressure of refrigerant isdecreased in order to maintain the function of the refrigerating cycle.Then, refrigerant having such a decreased evaporating pressure exhibitsfurther decrease of the evaporating temperature, and as a result, thetemperature of the outside heat exchanger 202 becomes lower by 12° C. ormore than the temperature of outside air supplied to the outside heatexchanger 202. Further, the reason why it is judged whether or not therefrigerant supplying time to the outside heat exchanger 202 has elapsedfor more than one hour is that normally it is a phenomenon which appearsafter continuous operation for more than one hour that frost appears onthe outside heat exchanger 202 to such a degree that it has asignificant effect on the heating performance of the outside heatexchanger 202.

A condition of the outside heat exchanger 202 is detected in this mannerat step 452, and if no frost is determined, then heating operation iscontinued. On the contrary if a frosted condition is determined at step452, then a display of such frosting is provided at step 452. Thepassenger can find the necessity of defrosting from the frostingdisplay. FIG. 52 shows an example of an operation panel which includesan LED 315 for displaying a frosted condition. The operation panelfurther includes a defrosting switch 314 for starting defrosting, and ifthe defrosting switch 314 is switched on, then this is detected at step453. In response to such detection, the operation of the automotive airconditioner is changed over to dehumidifying operation. It is to benoted that the dehumidifying operation in this instance is arefrigerating cycle wherein the outside heat exchanger 202 acts as acondenser. In other words, even in dehumidifying operation, a cyclewherein the outside heat exchanger 202 acts as an evaporator is exceptedin the present control.

It is to be noted that, with the operation panel shown in FIG. 52, notonly operation of the automotive air condition but also operation of theblower 132 are stopped simultaneously by means of a stop switch 307.When only the blower 132 is to operate, a blower switch 316 will beswitched on. Changing over of the capacity of the blower 132 upon airblasting is performed by way of the switch 301.

In order to facilitate defrosting, the compressor 201 has a greatcapacity. Further, the inside/outside air changing over damper 131 ischanged over to an inside air mode position so that the heating capacitymay not be deteriorated when dehumidifying operation is entered.Further, the auxiliary heaters 700 and 701 are rendered operative ifnecessary. Besides, the blowing air amount of the blower 132 isdecreased to prevent a drop of the blown out air temperature. Inaddition, the blower 251 for the outside heat exchanger 202 is stopped.

As a result, high pressure refrigerant discharged from the compressor201 is supplied into the outside heat exchanger 202 so that frostadhering closely to the surface of the outside heat exchanger 202 can bemelted by heat of the refrigerant.

It is to be noted that, while, in the flow chart shown in FIG. 48,dehumidifying operation is performed when defrosting is required,alternatively dehumidifying operation having some heating effect andheating operation may be performed alternately as seen from the flowchart shown in FIG. 49. In particular, as seen at step 454 of FIG. 49,dehumidifying operation and heating operation may be performedalternately in such a manner that dehumidifying operation is performedfor a predetermined period of time, for example, for 1 to 5 minutes orso after heating operation has been performed for another predeterminedperiod of time, for example, for 30 minutes to one hour.

It is to be noted that, in this instance, the condition whether or notthe function of the outside heat exchanger 202 as an evaporator hascontinued for more than one hour is eliminated from the conditions fordetection of frosting at step 452. In other words, presence or absenceof frost is judged depending upon whether or not the temperature of theoutside heat exchanger 202 is lower by more than the predeterminedtemperature than the temperature of outside air and whether or not thetemperature of the outside heat exchanger 202 is lower than -3° C. Here,the temperature difference between the temperature of the outside heatexchanger 202 and the temperature of outside air is not set to 12° C. ormore as at step 452 of the flow chart shown in FIG. 48 but set to 8° C.or more at step 452 of the flow chart shown in FIG. 49. This is becauseit is intended to precautionarily detect possible or forecast frost onthe outside heat exchanger 202 before the outside heat exchanger 202 iscompletely frosted.

Further, in the present flow chart, in dehumidifying operation havingsome heating effect at step 454, the inside/outside air changing overdamper 131 need not completely be changed over to its inside airadmitting position but may be set to another position at which both ofinside air and outside air can be admitted.

Subsequently, dehumidifying operation having some heating effectdescribed in the control above will be described.

In dehumidifying operation, air is first cooled in the evaporator 207and then heated in the condenser 203, but since heat is used forsensible heat for condensing moisture in air in the evaporator 207 asdescribed hereinabove, the temperature of the air is not lowered verymuch, and as a result, the temperature or air having passed both of theevaporator 207 and the condenser 203 rises. Further, since dehumidifyingoperation involves at least three heat exchangers including thecondenser 203, the evaporator 207 and the outside heat exchanger 202,the refrigerant condensing pressure, that is, the condensingtemperature, of the condenser 203 can be variably controlled by variablycontrolling the heat exchanging capacity of the outside heat exchanger202. For example, when both of the condenser 203 and the outside heatexchanger 202 perform a condensing action in such a refrigerating cycleas shown in FIG. 21, the condensing capacity as a refrigerating cyclecan be varied by controlling the blower 251 for the outside heatexchanger 202. When the blower 251 operates to blast a great amount ofair, the condensing capacity is increased, and as a result, thecondensing pressure of refrigerant is lowered. This signifies a drop ofthe condensing temperature of refrigerant and will cause a drop of thetemperature of the condenser 203.

On the contrary when the blower 251 stops its operation, the heatexchanging capacity of the outside heat exchanger 202 is lowered, and asa result, the condensing capacity of the refrigerating cycle is lowered.Consequently, the condensing pressure of refrigerant is increased andthe condensing temperature of refrigerant in the condenser 203 israised. This will raise the temperature of the condenser 203, therebyachieving dehumidifying operation having some heating effect.

Various means for varying the condensing capacity of the outside airconditioner may be available in addition to such control of the blower251 as described above.

For example, in a refrigerating cycle which employs a damper such as therefrigerating cycle shown in FIG. 14 which employs the damper 253, thecircuit of the damper 253 may be controlled so as to regulate the amountof air to be admitted into the outside heat exchanger 202 thereby tovary the heat exchanging capacity of the outside heat exchanger 202.Further, where the outside heat exchanger 202 is divided into aplurality of outside heat exchangers, the heat exchanging capacity maybe controlled by controlling the effective heat exchanging area of theoutside heat exchanger 202. Further, if necessary, coolant such as wateris flowed into the outside heat exchanger, and the amount of the coolantmay be controlled to control the heat exchanging capacity of the outsideheat exchanger 202.

Further, in an apparatus wherein air to be admitted into the outsideheat exchanger 202 is changed over between outside air and air in theroom of the automobile, the temperature of air to be admitted into theoutside heat exchanger 202 may be varied to control the heat exchangingcapacity of the outside heat exchanger 202.

Further, in such an apparatus as shown in FIG. 33 wherein refrigerantdischarged, upon dehumidifying operation, from the compressor 201 issupplied in parallel to both of the condenser 203 and the outside heatexchanger 202, the flow rate of refrigerant to be supplied to the heatexchanger 202 may be varied by opening/closing control of the valve 294.In particular, when the valve 294 is in an open condition, refrigerantflows to both of the outside heat exchanger 202 and the condenser 203 sothat a sufficient condensing action is performed by the two heatexchangers 202 and 203. On the contrary when the valve 294 is closed, acondensing action is performed only in the condenser 203, andconsequently, the condensing capacity is low.

The capacity controls of the outside heat exchanger 202 described abovemay be used not only for dehumidifying operation having some heatingeffect but also for control of the an entire refrigerating cycle. Forexample, when the pressure of the high pressure side refrigerant risesabnormally during dehumidifying operation, the capacity of the outsideheat exchanger 202 may be varied in order to protect the refrigeratingcycle.

FIG. 50 shows a flow chart of operation for controlling the blower 251for the outside heat exchanger 202 for the object described just above.Where fleon R22 is employed as refrigerant, when the high pressure siderefrigerant pressure becomes higher than 24.5 kg/cm² G, the blower 251is rotated at a high speed. On the contrary when the high pressure siderefrigerant temperature becomes lower than 22.5 kg/cm² G, the blower 251is stopped. In an intermediate region between them, the blower 251 isrotated at a low speed with some predetermined hysteresis.

FIG. 51 shows a control flow chart when capacity control of the outsideheat exchanger 202 is executed in order to achieve both of protection ofthe refrigerating cycle and achievement of agreeability in operation,upon dehumidifying operation, a pressure on the high pressure side ofthe refrigerating cycle is compared with a preset value at step 460. Ifthe high pressure side pressure is higher than the preset value, forexample, 24.5 kg/cm² G, then the capacity of the blower 251 for theoutside heat exchanger 202 is increased at step 461. Consequently, thecondensing capacity is enhanced and a rise in pressure to a highpressure in the refrigerating cycle is prevented.

In case it is determined that the high pressure side pressure is nothigher than the preset value, a room temperature is compared with apreset temperature subsequently at step 462.

In case the room temperature is higher by 1° C. or more than the presettemperature, it is determined that the heating capacity is not requiredvery much any more, and the amount of air of the blower 251 is increasedto increase the condensing capacity. On the contrary, when the roomtemperature is lower by 1° C. or more than the preset temperature, it isdetermined that an increase of the heating capacity is required, and theamount of air to be blasted from the blower 251 is decreased.Consequently, the condensing capacity of the outside heat exchanger 202is decreased thereby to increase the condensing pressure and thecondensing temperature of the condenser 203.

If the room temperature is within ±1° C. of the preset temperature, thecurrent condition of the blower 251 is maintained after then.

FIG. 53 shows a yet further automotive air conditioner according to thepresent invention. In the present automotive air conditioner, threeheaters 203 are arranged in series at three stages in the direction of aflow of air in the duct 100. A temperature sensing tube 204 is disposedat a refrigerant pipe on the upstream side of the subcooler 203c whichis positioned on the most upstream side in the direction of a flow ofair among the heaters 203, and the expansion valve 206 variably controlsthe refrigerating passage so that refrigerant may present apredetermined temperature at the entrance of the subcooler 203c.

In the present automotive air conditioner, the expansion valve 206controls the refrigerant passage so that refrigerant having passed thecondenser 203b has a subcooling degree of 2 to 3° C. When thetemperature of air which passes the heaters 203 is low or when the flowrate of air is high, refrigerant is liable to be condensed in theheaters 203 and refrigerant having passed the condenser 203b maypossibly have a sufficient subcooling degree. In this instance, a dropof the temperature of refrigerant is detected by the temperature sensingtube 204 and fed back to the expansion valve 206, and consequently, theexpansion valve 206 varies the refrigerating passage in an expandingdirection. As a result, the pressure of refrigerant on the heaters 203side is dropped, and the subcooling degree of refrigerant upon passageof the condenser 203b is decreased.

On the contrary when the flow rate of air to be admitted into theheaters 203 is low or the like, sufficient radiation of heat cannot beperformed with the condensers 203a and 203b. As a result, even afterrefrigerant passes the condenser 203b, a sufficient subcooling degree ofrefrigerant cannot be achieved. In this condition, the temperature ofrefrigerant at the heat sensing tube 204 rises, and a signal thereof isfed back to the expansion valve 206. Consequently, the expansion valve206 varies the refrigerating passage in a narrowing direction. As aresult, the pressure of refrigerant in the heaters 203 on the downstreamside of the expansion valve 206 is raised, and refrigerant becomesliable to be condensed. In other words, it becomes liable to achievesubcooling with an equal flow rate of air.

In this manner, the subcooling degree of refrigerant at the location ofthe temperature sensing tube 204 can be maintained to a predeterminedvalue by variably controlling the passage of refrigerant by means of theexpansion valve 206 in response to the temperature sensing tube 204.

Since, in the present automotive air conditioner, refrigerant at thelocation of the temperature sensing tube 204 has the subcooling degreeof 2 to 3° C. as described above, the subcooler 203c located on thedownstream side of the temperature sensing tube 204 in a flow ofrefrigerant can provide a subcooling degree of refrigerant withcertainty.

In particular, since the subcooler 203c admits on the entrance sidethereof refrigerant which already has a predetermined (2 to 3° C.)subcooling degree, refrigerant after passing the subcooler 203c has ahigher subcooling degree. While the width of the subcooling degree isnot fixed depending upon the temperature and/or the flow rate of airadmitted into the subcooler 203c, the subcooling degree can be increasedwith certainty.

To increase the subcooling degree leads to an increase of the enthalpyof refrigerant on the heat radiation side and hence to enhancement ofthe operation efficiency of the refrigerating cycle.

Particularly in the present automotive air conditioner, since thesubcooler 203c is disposed on the downstream side of the location of thetemperature sensing tube 204, improvement in operation efficiency of therefrigerating cycle can be achieved with certainty by subcooling by thesubcooler 203c. Particularly where the subcooler 203c is used togetherwith the air mixing damper 154 as in an automotive air conditioner, theflow rate of air flowing into the heaters 203 side varies to a greatextent in response to the opening of the air mixing damper 154. Further,the temperature of air flowing into the heaters 203 is different to agreat extent between that when refrigerant flows through the evaporator207 and that when refrigerant flows along the bypass passageway 230bypassing the evaporator 207.

In this manner, in an automotive air conditioner, since the flow rateand the temperature of air flowing into the heaters 203 vary to a greatextent, in order to assure a subcooling degree in any operatingcondition, preferably the subcooler 203c is disposed on the downstreamside of the temperature sensing tube 204 as in the present automotiveair conditioner.

Further, in the automotive air conditioner of FIG. 53, a shutter 255 forlimiting admission of air is provided forwardly of the outside heatexchanger 202. The shutter 255 corresponds to the function of the damper253 in the automotive air conditioner shown in FIG. 14, and theoccupying area can be reduced by provision of the shutter 255 shown inFIG. 53 in place of the damper 253. Further, the automotive airconditioner shown in FIG. 53 includes, similarly to the automotive airconditioner shown in FIG. 18, a fan 251 for electrically controlling airto be admitted into the outside heat exchanger 202.

The shutter 255 described above is particularly effective upondefrosting operation of the refrigerating cycle. The defrostingoperation is operation wherein refrigerant in a high temperature, highpressure condition is admitted, when frost on the outside heat exchanger202 is detected during heating operation, into the outside heatexchanger 202 to raise the temperature of the outside heat exchanger 202to melt the frost frozen on the outside heat exchanger 202. Sincedefrosting operation is performed during heating operation wherein thetemperature of outside air is low in this manner, if a large amount ofoutside air is admitted into the outside heat exchanger duringdefrosting operation, then much time is required for such defrosting anddefrosting may sometimes be impossible. Particularly with an automotiveheat exchanger, since the outside heat exchanger 202 is disposed at aposition at which it likely meets with a driving wind of the vehicle, itwill have a significant influence upon defrosting operation that theoutside heat exchanger 202 is cooled by a driving wind during running ofthe automobile.

Thus, with the present automotive air conditioner, upon defrostingoperation, the shutter 255 is closed to prevent a driving wind frombeing admitted into the outside heat exchanger 202, and also operationof the fan 251 for the outside heat exchanger 202 is stopped.

Subsequently, a controlling method for the refrigerating cycle shown inFIG. 53 will be described. Judgment whether the refrigerating cycleshould operate in heating operation, dehumidifying heating operation,dehumidifying operation, cooling operation or defrosting operation forthe outside heat exchanger is made in accordance with a flow ofoperations similar to that of the control shown in FIG. 48. The four-wayvalve 213, solenoid valve 231 and shutter 255 are opened and closed inthe individual modes in such a manner as seen from FIG. 54.

It is to be noted that the four-way valve 213 is changed over, similarlyas in the automotive air conditioners described hereinabove, between aposition (cooler condition) in which refrigerant discharged from thecompressor 201 flows to the outside heat exchanger 202 side andreturning refrigerant from the evaporator 207 side is sucked into thecompressor 201 and another position (heater condition) in whichrefrigerant discharged from the compressor 201 flows to the heaters 203side and returning refrigerant is sucked from the outside heat exchanger202 into the compressor 201.

Meanwhile, the solenoid valve 231 opens or closes the bypass passageway230 for flowing refrigerant bypassing the evaporator 207 therethrough.Accordingly, when the solenoid valve 231 is open, refrigerant flowsthrough the bypass passageway 230 and does not substantially flow to theevaporator 207 side. On the contrary, when the solenoid valve 231 is ina closed condition, refrigerant flows to the evaporator 207 side.

As seen from the control illustrated in FIG. 54, upon heating operationand upon dehumidifying heating operation, the four-way valve 213 ischanged over to the heater condition, in which refrigerant in a hightemperature, high pressure condition is supplied lo the heaters 203. Onthe other hand, upon dehumidifying operation, upon cooling operation andupon defrosting operation, the four-way valve 213 is changed over to thecooler condition wherein refrigerant in a high temperature, highpressure condition is supplied to the outside heat exchanger 202.

The solenoid valve 231 is opened only upon heating operation but isclosed in any other mode. In particular, only upon heating operation,refrigerant flows bypassing the evaporator 207. As a result, uponheating operation, the evaporator 207 does not function, and air flowingin the duct 100 is not cooled by the evaporator 207 at all. In any otheroperation condition, refrigerant is supplied into the evaporator 207after passing the capillary tube 211, and the evaporator 207 functionsas a cooler for air.

The shutter 255 is closed only upon defrosting of the outside heatexchanger 202 as described above but is open in any other operationcondition.

In a heating condition A and a dehumidifying heating condition B of FIG.54, such control as illustrated in FIG. 55 is executed. In particular,referring to FIG. 55, in a heating operation condition, the fan 251 forthe outside heat exchanger 202 is rotated at its maximum speed at step470. Consequently, when the heat pump is operated, absorption of heatfrom outside air is maximized.

In particular, upon heating operation, refrigerant discharged from thecompressor 201 flows through the four-way valve 213 into the heaters203, in which it is condensed and liquefied, whereafter it flows throughthe expansion valve 206 and the bypass passageway 230 into the outsideheat exchanger 203. Thus, the outside heat exchanger 202 acts as anevaporator to evaporate the refrigerant, and after then, the refrigerantis fed back to the compressor 201 by way of the four-way valve 203.Accordingly, since, upon heating operation, refrigerant is evaporated inthe outside heat exchanger 202 to absorb heat from outside air, also theoutside heat exchanger 201 to maximize the amount of heat to be absorbedis rotated at its maximum speed.

The speed of rotation of the compressor 201 is determined from a resultof comparison between an aimed blown out air temperature TAO and a blownout air temperature TA. The blown out air temperature TA is determinedin accordance with a signal from the blown out air temperature sensor323. The blown out air temperature sensor 323 is disposed at a positionat which, a warm wind having passed the heaters 203 and a cool windhaving bypassed the heaters 203 are mixed with each other. When theaimed blown out air temperature is higher than the actual blown out airtemperature, this condition is determined at step 471, and the frequencyof the invertor is increased at step 472. On the contrary when theactual blown out air temperature TA is higher than the aimed blown outair temperature TAO, the frequency of the invertor is decreased at step473.

The air mixing damper 154 is positioned at step 474 such that the entireamount of air is not flown to the heaters 203 side in order to prevent acool wind from being blown out into the room of the automobile uponheating operation and also upon dehumidifying heating operationdescribed below.

Subsequently, control of dehumidifying heating operation B of FIG. 54will be described.

In dehumidifying heating operation, the solenoid valve 231 is closed sothat refrigerant flows to the evaporator 207 side. In particular, inthis condition, the heater 204 acts as a condenser while both of theevaporator 207 and the outside heat exchanger 202 operate asevaporators.

It is judged at step 475 whether or not the temperature of air havingpassed the evaporator 207 is equal to or lower than 3° C. It is to benoted that the air temperature is judged in accordance with a signalfrom a temperature sensor 361 disposed on the downstream side of theevaporator 207. When the air temperature is higher than 3° C., the heatexchanging capacity of the outside heat exchanger 202 is lowered and thefan 251 for the outside heat exchanger 202 is stopped in order to lowerthe evaporating pressures in the evaporator 207 and the outside heatexchanger 202 at step 276.

In any other condition, the speed of rotation of the fan 251 for theoutside heat exchanger 202 is controlled in accordance with a result ofcomparison between the aimed blown out air temperature and the actualblown out air temperature. In case the aimed blown out air temperatureis higher than the actual blown out air temperature TA, this conditionis detected at step 477, and the speed of rotation of the fan 251 forthe outside heat exchanger 202 is raised at step 478. Consequently, theamount of heat to be absorbed in the outside heat exchanger 202 isincreased to raise the blown out air temperature. On the contrary, whenthe actual blown out air temperature TA is higher than the aimed blownout air temperature TAO, the speed of rotation of the fan 251 is loweredso as to lower the amount of heat to be absorbed in the outside heatexchanger 202.

While rotation of the fan 251 for the outside heat exchanger 202 iscontrolled in response to the aimed blown out air temperature TAO inthis manner, when the rotation is in an intermediate region or isadvancing from a maximum or minimum region to the intermediate region,this condition is detected at step 480, and the air mixing damper 154 isopened to its maximum opening at step 474. In any other condition, thecontrol sequence advances to step 471 to control rotation of theinvertor for the compressor 201.

In particular, in the control illustrated in FIG. 55, control of thecapacity of the refrigerating cycle upon dehumidifying heating is firstexecuted by the fan 251 for the outside heat exchanger 202, and onlyafter rotation of the fan 251 for the outside heat exchanger 202 becomesequal to its maximum or minimum, control of the discharging capacity ofthe compressor 201 by the invertor is executed.

Subsequently, dehumidifying operation C shown in FIG. 54 will bedescribed.

In such dehumidifying operation, the four-way valve 213 is changed overso that the outside heat exchanger 202 and the heaters 203 act ascondensers and evaporation of refrigerant is performed in the evaporator207.

Also upon dehumidifying operation, it is judged at step 475 whether ornot the temperature of outside air is equal to or lower than 3° C., andin case the outside air temperature is equal to or lower than 3° C., thefan 251 for the outside heat exchanger 202 is stopped at step 476.Further, in this instance, the circuit of the air mixing damper 154 ischanged over at step 481 to a condition wherein the entire amount of airflows to the heaters 203 side.

Temperature control of the refrigerating cycle when the outside airtemperature is higher than 3° C. is performed first by the air mixingdamper 154 and then by the fan 251 for the outside heat exchanger 251and finally by capacity control of the compressor 281. The capacitycontrols of the outside heat exchanger and the compressor are similar tothose in a dehumidifying heating operation condition describedhereinabove.

In the control by the air mixing damper 154, before it is detected atstep 482 whether or not the air mixing damper 154 is at its maximumheating position, the aimed blown out air temperature TAO and the actualblown out air temperature TA are compared with each other at step 483and then the opening of the air mixing damper 154 is regulated at step484 or 485.

Subsequently, cooling operation D in FIG. 54 will be described withreference to FIG. 57.

Upon cooling operation, refrigerant first flows into the outside heatexchanger 202 and is then decompressed and expanded in the expansionvalve 206 after passing the heaters 203, whereafter it flows into theevaporator 207. The refrigerant is thus evaporated in the evaporator 207and then returns to the compressor 207 by way of the accumulator 212.Upon such heating operation, since air is not heated by the heaters 203,the air nixing damper 154 is displaced at step 486 to a position atwhich it closes the heaters 203. Meanwhile, since the outside heatexchanger 202 operates as a condenser, rotation of the fan 251 for theoutside heat exchanger 202 is raised to its maximum in order to maximizethe heat radiating capacity of the condenser 202 at step 487. In thiscondition, control of the cooling capacity is performed by varying thedischarging capacity of the compressor 201 at steps 471 and 272 or 473.

Subsequently, defrosting operation E in FIG. 54 will be described withreference to FIG. 58.

In defrosting operation, a flow of refrigerant is basically similar tothat in cooling operation, and refrigerant in a high temperature, highpressure condition flows into the outside heat exchanger 202. However,in order to quicken defrosting, the shutter 255 is closed as describedhereinabove. Further, since this condition is basically a conditionwherein heating is required, the air mixing damper 154 is displaced atstep 488 to a position at which the entire amount of air flows to theheaters 203 side. Further, the fan 251 for the outside heat exchanger202 is stopped or kept inoperative at step 489 so that a cool wind maynot come to the outside heat exchanger 202. Further, in order tocomplete defrosting in a short interval of time. Fine invertor iscontrolled to maximize the discharging capacity of the compressor 201 atstep 490.

Operating conditions of the four-way valve 213, the solenoid valve 231,the shutter 255, the air mixing damper 154, the fan 251 for the outsideheat exchanger 202 and the invertor for controlling the dischargingamount of the compressor 201 in the various operation conditionsdescribed above are listed up in the table shown in FIG. 59.

Further, directions of flows of refrigerant in the heating operationcondition, the dehumidifying heating operation condition, the heatingoperation condition and the defrosting operation condition describedabove are shown in FIGS. 60 to 63, respectively. A flow of refrigerantis indicated by a thick line in each of FIGS. 60 to 63.

In the heating operation condition shown in FIG. 60, the heaters 203operate as condensers and a subcooler: the outside heat exchanger 202operates as an evaporator: and the evaporator 207 disposed in the duct100 does not operate. This is intended to prevent cooling of air in theduct 100 upon heating by keeping the evaporator 207 inoperative.

However, when the heating load is particularly high such as upon warmingup immediately after starting of heating, the refrigerating cycle is setsimilarly as in dehumidifying heating operation shown in FIG. 61 suchthat refrigerant flows also to the evaporator 207 so that the evaporator207 may operate as a heat sink.

This arises from the facts that, since the temperature of air sucked islow when the heating load is high in this manner, a drop of thetemperature of air by the evaporator 207 does not matter very much, thatabsorption of heat at the evaporator 207 is cancelled by a variation ofvisible heat of air and the temperature of air itself does not drop verymuch, and that, since absorption of heat in the entire refrigeratingcycle is performed in both of the evaporator 207 and the outside heatexchanger 202, the amount of absorbed heat is increased and as a resultthe amount of heat radiation from the heaters 203 is increased.

In particular, while heat of air sucked into the evaporator 207 isabsorbed in the evaporator 207, heat absorption then is performed firstby condensation of water in air, and consequently, the temperature ofthe air is not lowered very much even after it passes the evaporator207. Rather, a rise of the amount of heat radiation of the heaters 203acts effectively upon a rise of the temperature. In particular, theamount Of heat radiation of the heaters 203 results immediately in arise of the temperature of air passing the heaters 203, and there is novariation in latent heat.

Besides, since absorption of heat is performed in both of the evaporator207 and the outside heat exchanger 202, the amount of heat absorption Isincreased and as a result, the evaporating pressure of refrigerant israised. As the evaporating pressure rises, the specific volume ofrefrigerant sucked into the compressor 201 is decreased, andconsequently, the flow rate by weight of recirculating refrigerant bythe compressor is increased. In this manner, also the amount of heat ofrefrigerant supplied to the heaters 203 is increased and the amount ofheat radiation by the heaters 203 is increased.

However, since the operation condition requires higher power for thecompressor 201, such a flow of refrigerant as shown in FIG. 60 is takenin normal heating operation as described hereinabove.

FIG. 64 shows an example of a controlling operation panel for the cycleof the automotive air conditioner shown in FIG. 53. Since the automotivea conditioner shown in FIG. 53 has a dehumidifying heating operationmode as described hereinabove, a switch for dehumidifying heating isadditionally provided comparing with the panel shown in FIG. 52.

A yet further automotive air conditioner according to the presentinvention will be described with reference to FIG. 65. The automotiveair conditioner shown in FIG. 65 eliminates the evaporating pressureregulating valve 208 comparing with the automotive air conditioner shownin FIG. 53.

Prior to description of control of the automotive air conditioner shownin FIG. 65, a function of the evaporating pressure regulating valve 208will be described first with reference to FIG. 53. The evaporatingpressure regulating valve 208 is provided to prevent frosting on thesurface of the evaporator 207 when, particularly upon dehumidifyingheating operation, both of the evaporator 207 and the outside heatexchanger 202 serve as heat sinks to effect evaporation of refrigerant.

In particular, since there is the possibility that frost may adhere tothe surface of the evaporator 207 when the evaporating pressure ofrefrigerant in the evaporator 207 is excessively lowered until therefrigerant evaporation temperature becomes lower Man the freezingpoint, the pressure of refrigerant at the exit of the evaporator 207 iskept higher than a predetermined value by means of the evaporatingpressure regulating valve 208 in order to prevent such possiblefrosting.

In the automotive air conditioner shown in FIG. 65, the function of theevaporating pressure regulating valve 208 is achieved by opening/closingmovement of the bypass passageway 230. In particular, also in thepresent automotive air conditioner, both of the evaporator 207 and theoutside heat exchanger 202 operate, upon dehumidifying heatingoperation, as heat sinks to effect evaporation of refrigerant similarlyas in the automotive air conditioner described hereinabove withreference to FIG. 53. In this instance, when the pressure of refrigerantin the evaporator 207 is lowered below a predetermined value, thiscondition is detected by means of a temperature sensor 329 disposed on arefrigerant pipe on the exit side of the evaporator 207 and the solenoidvalve 231 is opened. Since the communication resistance to refrigerantis lower in the bypass passageway 230 than in the evaporator 207, whenThe solenoid valve 231 is opened, refrigerant flows to the bypasspassageway 230 while admission thereof into the evaporator 207 side islimited. Due to the limit in supply amount of refrigerant, evaporationof refrigerant does not occur in the evaporator 207, and as a result,the cooling capacity of the evaporator 207 is decreased remarkably. Inthe meantime, since the temperature of air admitted into the evaporator207 is equal to a room temperature, if operation is continued in thecondition wherein the cooling capacity is decreased remarkably, thenfrost appearing on the surface of the evaporator 207 will be melted.

In this manner, the evaporation temperature of refrigerant in theevaporator 207 can be restricted within a predetermined width bycontrolling opening/closing movement of the solenoid valve 231 inresponse to a temperature of refrigerant on the exit side of theevaporator 207 in this manner, and as a result, a function similar tothat of the evaporating pressure regulating valve described hereinabovecan be achieved.

A yet further automotive air conditioner according to the presentinvention will be described with reference to FIG. 66. While in theautomotive air conditioner shown in FIG. 53, the bypass passageway Isprovided sidewardly of the heaters 203 and, upon cooling, the air mixingdamper 154 closes the heaters 203 so that air may flow along the bypasspassageway, the heaters 203 in the automotive air conditioner shown inFIG. 66 is disposed over the entire area in the duct 100.

Then, upon cooling a bypass passageway 234 is opened so that refrigerantmay not flow to the heaters 203. The bypass passageway 234 is providedto communicate a refrigerant pipe on the entrance side and anotherrefrigerant pipe on the exit side of the heaters 203 with each other,and a solenoid valve 232 for opening or closing the bypass passageway234 is disposed intermediately of the bypass passageway 234.

Accordingly, upon cooling operation, the solenoid valve 232 is opened toopen the bypass passageway 234. Simultaneously, another solenoid valve233 provided in the entrance side refrigerant pipe is closed so thatrefrigerant may not flow to the heaters 203.

Accordingly, upon cooling, refrigerant is not supplied to the heaters203, and refrigerant accumulated in the heaters 203 will have a highsubcooling degree. Since the expansion valve 206 is controlled so thatrefrigerant on the entrance side of the subcooler 203c may have apredetermined subcooling degree as described hereinabove, in a conditionwherein refrigerant is not supplied any more and has a predeterminedsubcooling degree in this manner, such signal is inputted to theexpansion valve 206 and consequently, the expansion valve 206 is openeduntil its opening area presents its maximum in order to maximize theflow rate of refrigerant. Accordingly, suitable cooling operation cannotbe performed in this condition. However, in the present automotive airconditioner, since the capillary tube 211 is provided in series to theexpansion valve 206, refrigerant is decompressed and expanded suitablyby the capillary tube 211 even in such a condition as described justabove.

Subsequently, a yet further automotive air conditioner according to thepresent invention will be described with reference to FIG. 67. Theautomotive air conditioner shown in FIG. 67 employs a receiver 205similarly to the automotive air conditioner shown in FIG. 3. In thepresent automotive air conditioner, however, the receiver 205 isdisposed between the exit side of the condenser 203b and the entranceside of the subcooler 203c of the heaters 203.

Since the receiver 205 has a gas/liquid interface and only deliversliquid refrigerant, liquid refrigerant is supplied with certainty to thesubcooler 203c. Consequently, the subcooler 203c can provide asubcooling degree of refrigerant with certainty.

As described hereinabove, when the air conditioner is used as anautomotive air conditioner, the variation in amount of air admitted intothe heaters 203 when the air mixing damper 154 is opened and closed andthe variation in temperature of air when the evaporator 207 operates anddoes not operate are great, but where the subcooler 203c is disposed onthe downstream of the receiver 205 as in the present automotive airconditioner, a sufficient subcooling degree can be obtained withcertainty in any operation condition.

Further, in the present automotive air conditioner, the expansion valve206 varies the throttling amount of the refrigerant pipe so that apredetermined dryness may be obtained for refrigerant on the suckingside of the compressor 201.

In particular, since the temperature sensing tube for the expansionvalve 206 is disposed between the four-valve 214 and the compressor 201,to whichever position the four-way valve 214 is changed over, atemperature of suction refrigerant returning to the compressor 201 canalways be detected.

It is to be noted that, in the automotive air conditioner shown in FIG.67, the auxiliary heater 700 is disposed on the downstream side of theheaters 203 in a flow of air in order to complement the heating capacityupon heating or upon dehumidifying heating.

A yet further automotive air conditioner according to the presentinvention will be described subsequently with reference to FIG. 68. Theautomotive air conditioner shown in FIG. 68 solves a disadvantage whenan evaporating pressure regulating valve of the fully closed type isemployed as the evaporating pressure regulating valve 208.

When the evaporating pressure regulating valve 208 is of the fullyclosed type, if cold air flows into the evaporator 207 as upon, forexample, starting at a low temperature, the temperature of refrigeranton the exit side of the evaporator 207 is lowered below a predeterminedvalue and consequently the evaporating pressure regulating valve 208will close the refrigerant pipe. If the refrigerant pipe is closed inthis manner refrigerant will not return to the compressor 201, andconsequently, such a disadvantage as seizure of the compressor 201 maytake place.

Therefore, in an operation condition wherein the evaporation pressureregulating valve 208 closes the refrigerant passage in this manner, thesolenoid valve 231 is opened temporarily so that refrigerant may flow tothe downstream side of the evaporating pressure regulating valve 208 byway of the bypass passageway 230 bypassing the evaporating pressureregulating valve 208. While, in this condition, the evaporator 207 doesnot function temporarily, if air to be sucked into the duct 100 ischanged over to inside air and the temperature of air passing the duct100 rises, then also the temperature of refrigerant in the evaporator207 rises, and consequently, the evaporating pressure regulating valve208 will open the refrigerant passage. Accordingly, after then, thebypass passageway 230 can be closed to flow refrigerant to theevaporator 207 side.

Accordingly, in the present automotive air conditioner, the bypasspassageway 230 is only required to bypass the evaporating pressureregulating valve 208 and need not necessarily bypass the evaporator 207.

Further, if the evaporating pressure regulating valve 208 is of the typewhich can pass a predetermined amount of refrigerant even when itassumes its minimum throttling condition, the bypass passageway 230 neednot necessarily be provided.

Subsequently, a yet further automatic air conditioner according to thepresent invention will be described with reference to FIG. 69. Theautomotive air conditioner shown in FIG. 69 can achieve defrosting ofthe outside heat exchanger 202 during heating operation and duringdehumidifying heating operation without considerable deterioration ofthe dehumidifying heating function. To this end, in the automatic airconditioner shown in FIG. 69, the three-way valves 275, 276 and 277 arechanged over to change over a sequence of a flow of refrigerant.

In particular, in any of heating operation and dehumidifying heatingoperation in which defrosting is involved, refrigerant in a hightemperature, high pressure condition is supplied from the compressor 201into the heater 203, which thus operates as a heat radiator. Further,refrigerant in a low temperature, low pressure condition is supplied toboth of the evaporator 207 and the outside heat exchanger 202, whichboth operate thus as heat sinks.

However, in heating operation and in dehumidifying heating operation inwhich defrosting is involved, refrigerant flows in different ordersthrough the evaporator 207 and the outside heat exchanger 202. Upondehumidifying heating operation, refrigerant condensed by the heater 203flows, after passing the expanding means 206, first into the evaporator207 and then into the outside heat exchanger 202.

This is intended, because it is normally forecast that the temperatureof outside air is low upon dehumidifying heating operation, to assureoperation of the automotive air conditioner even in such condition. Inparticular, when the outside air temperature is, for example, lower than0° C., the evaporating temperature of refrigerant is lower than thefreezing point and lower than the outside air temperature so thatrefrigerant may be evaporated in the outside heat exchanger 202 in suchoutside air temperature condition. Here, if the evaporator 207 isdisposed on the downstream side of the outside heat exchanger 202 in aflow of refrigerant, then the evaporating temperature of refrigerant inthe evaporator 207 will be lower than the evaporating temperature ofrefrigerant in the outside heat exchanger 202 and lower than thefreezing point. Consequently, frosting takes place on the surface of theevaporator 207 and the ventilation resistance in the duct 100 isincreased. As a result, good dehumidifying heating operation cannot beachieved.

On the other hand, if the evaporator 207 is disposed on the upstreamside of the outside heat exchanger 202 in a flow of refrigerant, thenthe evaporating temperature of refrigerant in the evaporator 207 can bemade higher than the evaporating temperature of refrigerant in theoutside heat exchanger 202. Consequently, the refrigerant temperature ofrefrigerant in the evaporator 207 can always be held to a predeterminedtemperature of 2 to 3° C.

In this instance, frosting of the outside heat exchanger 202 seems tomatter. However, since the disadvantage by frosting is more serious withthe evaporator 207 than with the outside heat exchanger 202, theevaporator 207 is disposed on the upstream side in a flow of refrigerantupon normal dehumidifying heating operation.

Then, in case frosting of the outside heat exchanger 202 becomesparticularly significant in such operation condition, the flow ofrefrigerant is changed over so that refrigerant having passed the heater203 first flows into the outside heat exchanger 202. Consequently,refrigerant in a high temperature, high pressure condition is suppliedinto the outside heat exchanger 202 to raise the temperature of thesurface of the outside heat exchanger 202. As a result, frost appearingon the surface of the outside heat exchanger 202 is melted. In thisoperation condition, operation of the fan 251 for the outside heatexchanger 202 is stopped in order to accelerate defrosting. Then, therefrigerant having passed the outside heat exchanger 202 is decompressedand expanded in the capillary tube 211 and then flows into theevaporator 207. Further, as described hereinabove, preferably an insideair mode is entered to set the amount of a wind of the inside blower tothe Lo position.

FIGS. 70 to 73 show flows of refrigerant in the automatic airconditioner shown in FIG. 69. In particular, FIG. 70 shows a heatingoperation condition and FIG. 71 shows a cooling operation condition.Further, FIG. 72 shows a dehumidifying heating operation condition, andFIG. 73 shows a condition wherein defrosting of the outside heatexchanger 202 is performed. In all of FIGS. 70 and 73, only a pipe inwhich refrigerant flows is indicated with a thick line.

Subsequently, a yet further automotive air conditioner according to thepresent invention will be described with reference to FIG. 74. Therefrigerating cycle shown in FIG. 74 is an accumulator cycle whichadditionally includes, comparing with the cycle shown in FIG. 21, apassageway 297 bypassing the capillary tube 211 and a solenoid valve 294for opening or closing the passageway 294.

Refrigerant flow passage changing over means changes over flowingdirections of refrigerant upon cooling operation, upon heatingoperation, upon dehumidifying operation, and upon defrosting operationduring dehumidifying operation (hereinafter referred to as defrostingoperation). Similarly as in the automotive air conditioner describedhereinabove, the refrigerant flow passage changing over means includes afour-way valve 213 for changing over the discharging direction of therefrigerant compressor 201 between that upon cooling operation and thatupon any other operation, a first solenoid opening/closing valve 201 forbypassing, upon heating operation, the first decompressing apparatus 211and the evaporator 207 on the upstream side, a second solenoidopening/closing valve 260 for bypassing, upon dehumidifying operation,the second decompressing apparatus 266, and a third solenoidopening/closing valve 298 for bypassing, upon defrosting operation, thefirst decompressing apparatus 211. A pair of check valves 262 and 265for controlling flowing directions of refrigerant are also provided.

The flow passage changing over means changes over a flow of refrigerantin the following manner upon cooling operation, upon heating operation,upon dehumidifying operation and upon defrosting operation.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of four-way valve 213→outside heatexchanger 202→first decompressing apparatus 211→evaporator207→accumulator 212→refrigerant compressor 201 (refer to arrow marks Cin FIG. 74).

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of four-way valve 213→heater203→second decompressing apparatus 266→outside heat exchanger 202→firstsolenoid opening/closing valve 261→accumulator 212→refrigerantcompressor 201 (refer to arrow marks H in FIG. 74).

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows In the order of four-way valve213→heater 203→second solenoid opening/closing valve 260→outside heatexchanger 202 (the outside blower 251 is inoperative then) →firstdecompressing apparatus 211→evaporator 207→accumulator 212→refrigerantcompressor 201 (refer to arrow marks D in FIG. 74).

Upon defrosting operation wherein defrosting of the evaporator 207 isperformed in a dehumidifying operation condition, refrigerant dischargedfrom the refrigerant compressor 201 flows in the order of four-way valve213→heater 203→second decompressing apparatus 266→outside heat exchanger202 (the outside blower 251 is operative then) →third solenoidopening/closing valve 298→evaporator 207→accumulator 212→refrigerantcompressor 201 (refer to arrow marks F in FIG. 74).

The controlling apparatus 300 includes a temperature sensor fordetecting a temperature of a fin or a tube of the evaporator 207 or atemperature of air having passed the evaporator 207. The temperaturesensor is provided to detect frost on the evaporator 207, and when thetemperature of the fin of the evaporator 207 detected by the temperaturesensor is lowered to 0° C. the controlling apparatus 300 forecastsfrosting and executes defrosting of the evaporator 207 in order toprevent frosting.

Subsequently, defrosting operation during dehumidifying operation of theautomotive air conditioner shown in FIG. 74 will be described.

If the temperature detected by the temperature sensor duringdehumidifying operation becomes lower than 0° C., then the controllingapparatus 300 closes the second solenoid opening/closing valve 260,opens the third solenoid opening/closing valve 298 and renders theoutside blower 251 operative to effect defrosting operation. Then, ifthe temperature detected by the temperature sensor rises higher than 1°C., then the controlling apparatus 300 opens the second solenoidopening/closing valve 260, closes the third solenoid opening/closingvalve 298 and renders the outside blower 251 inoperative to return theoperation to dehumidifying operation.

If dehumidification is set by means of the air conditioning mode settingswitch 314 of the operation panel by the passenger, then outside air orinside air selected by the inside/outside air changing over means 131 issucked into the duct 100 by the blower 132, passes through theevaporator 207, the heater 203 and the auxiliary heaters 700 and 701 andis blown out into the room of the automobile from a spit hole set by theblowing mode changing over switch 303. The amount of a wind then is setby means of the wind amount setting switch 301.

In the refrigerating cycle upon dehumidifying operation, refrigerant ina high temperature, high pressure condition discharged from therefrigerant compressor 201 is introduced into the heater 203 by means ofthe four-way valve 213. Here, the refrigerant exchanges heat with airflowing in the duct 100 to heat the air in the duct 100 while it iscondensed and liquefied in the heater 203. The thus liquefiedrefrigerant then flows into the outside heat exchanger 202 by way of thesecond solenoid opening/closing valve 260. In this instance, since theoutside blower 251 is inoperative, the liquefied refrigerant passesthrough the outside heat exchanger 202 and is then decompressed andexpanded into low temperature, low pressure mist in the firstdecompressing apparatus 211. The refrigerant in the form of mist flowsinto the evaporator 207, in which it takes heat away from air flowing inthe duct 100 so that it is evaporated. Then, the thus evaporatedrefrigerant is re-sucked into the refrigerant compressor 210 by way ofthe accumulator 212.

Air sucked into the duct 100 is lowered in temperature when it passesthe evaporator 203, and consequently, saturated vapor in the air iscondensed and adheres to the evaporator 207. After then, the air isheated when it passes the heater 203, and consequently, the moisture inthe air decreases remarkably. As a result, good dehumidifying operationis performed.

If the temperature of air sucked into the duct 100 during dehumidifyingoperation becomes so low that the temperature of the evaporator 207detected by the temperature sensor is lower than 0° C., then thecontrolling apparatus 300 controls the flow passage changing over meansto change over the refrigerant flow passage of the refrigerating cycleto that for dehumidifying operation. In short, the second solenoidopening/closing valve 260 is closed while the third solenoidopening/closing valve 298 is opened. Consequently, refrigerant condensedand liquefied in the heater 203 is decompressed and expanded into lowtemperature, low pressure mist in the first decompressing apparatus 266,and then flows into the outside heat exchanger 202. In this instance,since the outside blower 251 is operating, the outside heat exchanger202 functions as a refrigerant evaporator together with the evaporator207. The refrigerant admitted into the evaporator 207 by way of theoutside heat exchanger 202 and the third solenoid opening/closing valve298 exchanges heat with outside air passing the outside heat exchanger202 and also with air flowing in the duct 100 and passing the evaporator207 so that it is evaporated. The thus evaporated refrigerant is thenre-sucked into the refrigerant compressor 201 by way of the accumulator212.

The evaporating pressure is raised by using the outside heat exchanger202 as a refrigerant evaporator together with the evaporator 207.Consequently, while the evaporator 207 functions as a refrigerantevaporator, the temperature of the evaporator 207 rises and as a result,frosting of the evaporator 207 can be prevented.

Then, if the temperature of the fin of the evaporator 207 detected bythe temperature sensor becomes higher than 1° C., then the controllingapparatus 100 controls the flow passage changing over means to open thesecond solenoid opening/closing valve 253 and close the third solenoidopening/closing valve 293 to change over the refrigerant flow passage ofthe refrigerating cycle to that for dehumidifying operation. Further,the outside blower 251 is rendered inoperative, thereby performingdehumidifying operation described hereinabove. In the automotive airconditioner shown in FIG. 74, since the evaporator 207 in the duct 100always functions, upon dehumidifying operation, as a refrigerantevaporator such that dehumidifying operation is maintained even indefrosting operation as described hereinabove, the temperature in theroom of the automobile can normally be kept low. Further, sincedefrosting can be performed without lowering the capacity of therefrigerant compressor 201, no drop in blown out air temperature isinvited upon defrosting operation.

FIG. 75 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The present automotiveair conditioner includes a three-way valve 269 in place of the four-wayvalve 213 of the automotive air conditioner shown in FIG. 74 andadditionally includes a fourth solenoid opening/closing valve 268 forreturning, upon cooling operation, refrigerant accumulated in the heater203 to the accumulator 212.

FIG. 76 is a refrigerant circuit diagram of a yet further automotive airconditioner according to are present invention. The present automotiveair conditioner includes two fifth and sixth solenoid opening/closingvalves 270 and 271 in place of the three-way valve 269 of the automotiveair conditioner shown in FIG. 75.

FIG. 77 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The present automotiveair conditioner includes a three-way valve 272 in place of the fifthsolenoid opening valve 270 for changing over the discharging directionof the refrigerant compressor 201 in the automotive air conditionershown in FIG. 76 and the fourth solenoid opening/closing valve 268 forreturning, upon cooling operation, refrigerant accumulated in the heater203 to the accumulator 212.

FIG. 78 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The refrigerating cycleof the present automotive air conditioner is changed over in thefollowing manner in accordance with various operation modes by flowpassage changing over means.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→outside heatexchanger 202→seventh solenoid opening/closing valve 296→firstdecompressing apparatus 211→evaporator 207→accumulator 212→refrigerantcompressor 201 (refer to arrow marks C in FIG. 78).

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→heater203→second decompressing apparatus 266→seventh solenoid opening/closingvalve 296→outside heat exchanger 202→four-way valve 213→accumulator212→refrigerant compressor 201 (refer to arrow marks H in FIG. 78).

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of the four-way valve213→heater 203→second decompressing apparatus 266→eighth solenoidopening/closing valve 298→evaporator 207→accumulator 212→refrigerantcompressor 201 (refer to arrow marks D in FIG. 78).

Upon defrosting operation, refrigerant discharged from the refrigerantcompressor 201 passes in the order of the four-way valve 213→heater203→second decompressing apparatus 266. The refrigerant having passedthe second decompressing apparatus 266 As divided into two flows. In oneof the two flows, the refrigerant flows in the order of the eighthsolenoid opening/closing valve 298→evaporator 207→accumulator212→refrigerant compressor 201. Meanwhile, in the other flow, therefrigerant flows in the order of the seventh solenoid opening/closingvalve 296→outside heat exchanger 202→four-way valve 213→accumulator212→refrigerant compressor 201 (refer to arrow marks F in FIG. 78).

FIG. 79 shows a refrigerant circuit diagram of a yet further automotiveair conditioner according to the present invention. The refrigeratingcycle of the present automotive air conditioner is changed over in thefollowing manner in accordance with various operation modes by flowpassage changing over means.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→ninthsolenoid opening/closing valve 295→outside heat exchanger 202→tenthsolenoid opening/closing valve 291→first decompressing apparatus211→evaporator 207→accumulator 212→refrigerant compressor 201

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→heater203→eleventh solenoid opening/closing valve 292→second decompressingapparatus 266→outside heat exchanger 202→ninth solenoid opening/closingvalve 293→four-way valve 213→accumulator 212→refrigerant compressor 201.

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 is divided into two flows one of which flowsto the four-way valve 213 and the other of which flows to a twelfthsolenoid opening/closing valve 294. The refrigerant flowing to thefour-way valve 213 flows in the order of the four-way valve 213→heater203→tenth solenoid opening/closing valve 291→first decompressingapparatus 211→evaporator 207→accumulator 212→refrigerant compressor 201.On the other hand, the refrigerant flowing to the twelfth solenoidopening/closing valve 294 flows in the order of the twelfth solenoidopening/closing valve 294→outside heat exchanger 202→tenth solenoidopening/closing valve 291→first decompressing apparatus 211→evaporator207→accumulator 212→refrigerant compressor 212.

Upon defrosting operation, refrigerant discharged from the refrigerantcompressor 201 passes in the order of the four-way valve 213→heater 203.The refrigerant having passed the heater 203 is divided into two flows.In one of the two flows, the refrigerant flows in the order of the tenthsolenoid opening/closing valve 291→first decompressing apparatus211→evaporator 207→accumulator 212→refrigerant compressor 201.Meanwhile, in the other flow, the refrigerant flows in the order of theeleventh solenoid opening/closing valve 292→second decompressingapparatus 266→outside heat exchanger 202→ninth solenoid opening/closingvalve 293→four-way valve 213→accumulator 212→refrigerant compressor 201.

FIG. 80 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The present automotiveair conditioner adopts the construction wherein refrigerant always flowsin the evaporator 207. Thus, a bypass wind passageway for flowing airbypassing the evaporator 207 is provided in the duct 100, and uponheating operation, the evaporator 207 is closed by the damper 159 on theupstream side so that refrigerant may not exchange neat with air in theduct 100.

The refrigerating cycle of the present automotive air conditioner ischanged over in the following manner in accordance with variousoperation modes by flow passage changing over means.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→outside heatexchanger 202→first decompressing apparatus 211→evaporator207→accumulator 212→refrigerant compressor 201.

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→heater203→second decompressing apparatus 266→outside heat exchanger202→solenoid opening/closing valve 298→evaporator 207→accumulator212→refrigerant compressor 201.

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of the four-way valve213→heater 203→solenoid opening/closing valve 260→outside heat exchanger201→first decompressing apparatus 211→evaporator 207→accumulator212→refrigerant compressor 201.

Upon defrosting operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→heater203→second decompressing apparatus 266→outside heat exchanger202→solenoid opening/closing valve 298→evaporator 207→accumulator212→refrigerant compressor 201.

FIG. 81 is a refrigerant circuit diagram of a yet further automotive airconditioner according to the present invention. The present automotiveair conditioner adopts the construction wherein refrigerant always flowsin the evaporator 207. Thus, a bypass wind passageway for flowing airbypassing the heater 203 is provided in the duct 100, and upon coolingoperation, the heater 203 is closed by the damper 154 on the downstreamside so that refrigerant and air in the duct 100 may not exchange heatin the heater 203.

The refrigerating cycle of the present automotive air conditioner ischanged over in the following manner in accordance with variousoperation modes by flow passage changing over means.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→solenoidopening/closing valve 260→outside heat exchanger 202→first decompressingapparatus 211→evaporator 207→accumulator 212→refrigerant compressor 201.

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→second decompressingapparatus 266→outside heat exchanger 202→solenoid opening/closing valve261→accumulator 212→refrigerant compressor 201.

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of the heater 203→solenoidopening/closing valve 260→outside heat exchanger 202→first decompressingapparatus 211→evaporator 207→accumulator 212→refrigerant compressor 201.

Upon defrosting operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→second decompressingapparatus 266→outside heat exchanger 202→solenoid opening/closing valve298→evaporator 207→accumulator 212→refrigerant compressor 201.

A yet further automotive air conditioner according to the presentinvention can be attained by a circuit similar to the refrigeratingcircuit shown in FIG. 40. The present automotive air conditioner willthus be described with reference to FIG. 40. The present automotive airconditioner adopts the construction wherein refrigerant always flows inthe evaporator 207 and the heater 203. Thus, a bypass wind passagewayfor flowing air bypassing the evaporator 207 and another bypass windpassageway for flowing air bypassing the heater 203 are provided in theduct 100, and upon heating operation, the evaporator 207 is closed bythe damper 159 on the upstream side, but upon cooling operation, theheater 203 is closed by the damper 154 on the downstream side.

The refrigerating cycle of the present automotive air conditioner ischanged over in the following manner in accordance with variousoperation modes by flow passage changing over means.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→solenoidopening/closing valve 260→outside heat exchanger 202→first decompressingapparatus 211→evaporator 207→accumulator 212→refrigerant compressor 201.

Upon heating operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→second decompressingapparatus 266→outside heat exchanger 202→solenoid opening/closing valve261→evaporator 207→accumulator 212→refrigerant compressor 201.

Upon dehumidifying operation, refrigerant discharged from therefrigerant compressor 201 flows in the order of the heater 203→solenoidopening/closing valve 260→outside heat exchanger 202→first decompressingapparatus 211→evaporator 207→accumulator 212→refrigerant compressor 201.

Upon defrosting operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the heater 203→second decompressingapparatus 266→outside heat exchanger 202→solenoid opening/closing valve261→evaporator 207→accumulator 212→refrigerant compressor 201.

A yet further automotive air conditioner according to the presentinvention can be attained by a circuit similar to the refrigeratingcircuit shown in FIG. 7. The present automotive air conditioner willthus be described with reference to FIG. 7. The present automotive airconditioner adopts the construction wherein refrigerant always flows inthe evaporator 207 and the heater 203. Thus, a bypass wind passagewayfor flowing air bypassing the heater 203 is provided in the duct 100,and the opening of the damper 154 on the downstream side is varied toadjust the mount of air to pass the heater 203 and the amount of air topass the bypass passageway to adjust the blown out air temperature.

The refrigerating cycle of the present automotive air conditioner ischanged over in the following manner by flow passage changing over meanswhich employs two four-way valves 213 and 214.

Upon cooling operation and upon defrosting operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of thefour-way valve 213→outside heat exchanger 202→four-way valve 214→heater203→first decompressing apparatus 211→evaporator 207→four-way valve213→accumulator 212→refrigerant compressor 201.

Upon heating operation and upon defrosting operation, refrigerantdischarged from the refrigerant compressor 201 flows in the order of thefour-way valve 213→four-way valve 214→heater 203→first decompressingapparatus 211→evaporator 207→four-way valve 214→outside heat exchanger203→four-way valve 213→accumulator 212→refrigerant compressor 201.

Further, dehumidifying operation and defrosting operation can beachieved even with such a construction as shown in FIG. 11 wherein abypass wind passageway is formed sidewardly of the evaporator 207.

Further, dehumidifying operation and defrosting operation can beachieved similarly even with a construction wherein the four-way valve214 is replaced by four check valves 216, 217, 218 and 219 as shown inFIG. 13.

Further, while a temperature sensor is employed as a sensor fordetecting frost on the evaporator in the automotive air conditionersdescribed hereinabove, not a temperature but a pressure of refrigerantin the pipe on the exit side of the evaporator may alternatively bedetected to forecast frosting from an evaporating temperature ofrefrigerant. Or else, a sensor for detecting a loss in pressure of theevaporator may be used to detect frosting from a variation in loss inpressure of a wing passing the evaporator.

FIGS. 82 to 85 show refrigerating cycles of a yet further automotive airconditioner according to the present invention. In particular, FIGS. 82to 85 illustrate cooling, heating, dehumidifying heating and defrostingconditions, respectively, and indicate a pipe in which refrigerant flowsby a thick line. The expansion pipe 206 employed here is a temperaturedifferential expansion valve which varies the throttling amount of therefrigerant flow passage so that refrigerant on the exit side of theheater 203 adjacent the condenser may have a predetermined subcoolingdegree.

Upon cooling operation, refrigerant discharged from the refrigerantcompressor 201 flows in the order of the four-way valve 213→outside heatexchanger 202→expanding means 260→evaporator 207→accumulator212→refrigerant compressor 201.

Upon heating operation, refrigerant flows in the order of the compressor201→four-way valve 213→heater 203→expansion valve 206→outside heatexchanger 202→accumulator 212→refrigerant compressor 201.

When there is the possibility upon heating that the windshield may befogged, dehumidifying heating operation is performed, and in thisinstance, refrigerant flows in the order of the compressor 201→heater203→expansion valve 206→outside heat exchanger 202→solenoidopening/closing valve 266→evaporator 207→accumulator 212→refrigerantcompressor 201.

In case the surface of the outside neat exchanger 202 is frozen uponheating, the condition of the outside heat exchanger 202 is detected anddefrosting operation is started. Upon defrosting operation, refrigerantcirculates in the refrigerant cycle in the order of the refrigerantcompressor 201→heater 203→solenoid valve 298→outside heat exchanger202→expanding capillary tube 260→evaporator 207→accumulator212→compressor 201.

The difference of the refrigerating cycles from those of the automotiveair conditioner shown in FIG. 63 is that, while refrigerant flows, upondefrosting operation, in the order of the outside heat exchanger202→heater 203 in the automotive air conditioner shown in FIG. 63,refrigerant flows in the reverse order of the heater 203→outside heatexchanger 202 in the present automotive air conditioner. When dischargedrefrigerant flows, upon defrosting operation, first into the heater 203as in the present automotive air conditioner, a predetermined subcoolingdegree can always be obtained at the heater 203.

This will be described subsequently. Since, in the automotive airconditioner shown in FIG. 63, refrigerant is condensed first in theoutside heat exchanger 202, when the temperature of outside air is lowat 0° C. or so, it is forecast that refrigerant after passing theoutside heat exchanger 202 may be cooled to 10° C. or so and condensed.Here, if it is assumed that the refrigerant has a subcooling degree of 2to 3° C. or so when it passes the outside heat exchanger 202, thetemperature corresponding to a condensing pressure of the refrigerantwhen it passes the outside heat exchanger 202 is 12 to 13° C. or so. Onthe other hand, for a while after the operation is changed over fromheating operation to defrosting operation, air is not cooledsufficiently in the evaporator 207 and comparatively warm air of atemperature equal to the room temperature or so will flow into theheater 203. The air temperature is in most cases 12 to 13° C. or moreand may sometimes be higher than a temperature corresponding to thecondensing pressure described above. In this instance, refrigerantcondensed once in the outside heat exchanger 202 will be evaporatedagain when it passes the heater 203. The refrigerant does not have asubcooling degree at least when it passes the condenser portion of theheater 203. As a result, the expansion valve 206 of the temperaturedifferential type will throttle the flow rate of refrigerant so as toobtain a subcooling degree, and consequently, the amount of refrigerantwhich circulates in the cycle will be reduced remarkably.

On the other hand, in the automotive air conditioner shown in FIG. 85,since refrigerant discharged from the compressor 201 flows, even upondefrosting operation, similarly as upon heating operation, first intothe heater 203, such a disadvantage as described above does not occureven upon changing over from heating operation to defrosting operation.In the present automotive air conditioner, refrigerant having passed theheater 203 after defrosting is lowered in temperature, and while thetemperature of refrigerant in the outside heat exchanger 202 is lowcomparing with that of refrigerant which advances from the compressor201 directly to the outside heat exchanger 202, since refrigerant of atemperature higher than 0° C. flows any way into the outside heatexchanger 202, defrosting operation is achieved well.

It is to be noted that, while, in the automotive air conditionersdescribed above, the compressor 201 is driven by means of an electricmotor and the discharging capacity of the compressor 201 is controlledby varying the speed of rotation of the motor, the compressor 2C mayotherwise be of another type which does not nave a variable dischargingcapacity. Further, the compressor 201 need not necessarily be driven byan electric motor but may be driven by an engine or the like.

Further, while, in the automotive air conditioners described above, atemperature differential expansion valve or a capillary tube is employedas expanding means, alternatively an electric expansion valve whichvaries a throttling amount in response to an electric signal may beemployed.

Further, an automotive air conditioner according to the presentinvention may be used not only for air conditioning of a room of anelectric automobile but also for air conditioning of a room of anordinary automobile employing an internal combustion engine and anyother common vehicle. However, an automotive air conditioner accordingto the present invention is most effective for use with a vehicle whichdoes not have an auxiliary heat source such as an electric automobile.

As described so far, according to the present invention, since a heaterand an evaporator which constitute a refrigerating cycle is disposed ina duct and air is heated by radiation of heat from the heater, thetemperature of air to be blown out can be controlled in a wider range.

Further, according to the present invention, since heat exchangersdisposed in a duct have individually specified functions as a heater andan evaporator, even upon changing over from cooling operation to heatingoperation, the heat exchangers can maintain the respective functionsthereof, and sudden fogging of the windshield and so forth can beprevented.

Further, according to the present invention, since the dischargingcapacity of a compressor can be varied by controlling rotation of anelectric motor and a bypass passageway is provided sidewardly of aheater such that the flow rate of air may be controlled by means of anair mixing damper, the temperature of air to be blown out can becontrolled very finely by combination of control of the dischargingamount of the compressor and control of pivotal motion of the air mixingdamper.

Further, according to the present invention, since the function of anoutside heat exchanger is changed over between a condenser function andan evaporator function in response to changing over between coolingoperation and heating operation, the refrigerating cycle can be operatedefficiently in any of cooling operation, heating operation anddehumidifying operation.

Further, according to the present invention, since two outside heatexchangers are used including an outside condenser which serves only asa condenser and an outside evaporator which serves only as anevaporator, the outside condenser and the outside evaporator can belocated at respective optimum positions, and the refrigerating cycle canbe achieved efficiently.

Further, according to the present invention, since the operation can bechanged over successively between dehumidifying operation and heatingoperation in accordance with an application, prevention of fogging ofthe windshield upon heating operation, prevention of freezing of anevaporator upon dehumidifying operation and defrosting of an outsideheat exchanger upon heating operation can be performed well.

Further, according to the present invention, making use of the fact thatthree heat exchangers are used upon dehumidifying operation including anoutside heat exchanger, a condenser and an evaporator, the heatradiating capacity of the condenser can be controlled by varying theheat exchanging capacity of the outside heat exchanger. Consequently,dehumidification can be changed over between ordinary dehumidificationand dehumidification having some heating effect. In addition, protectionof the refrigerating cycle against a high pressure upon dehumidifyingoperation can be achieved well.

Further, according to the present invention, while both of an evaporatorand an outside heat exchanger are used as heat sinks to evaporaterefrigerant upon dehumidifying operation, since an evaporating pressureregulating valve is disposed on the downstream side of the evaporator,even when the temperature of outside air is low, dehumidifying operationcan be performed while preventing frosting of the evaporator well.

Further, according to the present invention, since a bypass passagewayfor flowing refrigerant bypassing an evaporator is provided andopening/closing movement of the bypass passageway is controlled by meansof a solenoid valve, the evaporating temperature of refrigerant in theevaporator can be controlled by suitably changing over between acondition wherein refrigerant flows into the evaporator and anothercondition wherein refrigerant flows into the bypass passageway.

Further, according to the present invention, since a heater disposed ina duct is divided into a condenser for condensing refrigerant and asubcooler for subcooling condensed liquid refrigerant, refrigerant canhave a subcooling degree with certainty even if the flow rate or thetemperature of air to be admitted into the heater varies. Consequently,according to the present invention, the refrigerating cycle can alwaysbe operated while refrigerant has a sufficient subcooling degree, andefficient operation can be achieved.

Further, according to the present invention, since the heat absorbingcondition upon heating operation is changed over between a conditionwherein heat is absorbed only by means of an outside heat exchanger andanother condition wherein heat is absorbed by means of both of theoutside heat exchanger and an evaporator, when the heating load isparticularly high such as upon warming up, heat is absorbed also fromthe evaporator side and heating can be achieved quickly.

We claim:
 1. An automotive air conditioner, comprising:a duct defining apassageway for conditioned air to a room of an automobile; a blower forblowing air toward the room of the automobile by way of said duct; anevaporator disposed in said duct for evaporating refrigerant to coolair; a heater disposed on the downstream side of said evaporator in saidduct for causing refrigerant of a high temperature and air to exchangeheat with each other to heat the air; a compressor for compressing anddischarging refrigerant; an outside heat exchanger disposed outside saidduct for causing air outside said duct and refrigerant to exchange heatwith each other; an accumulator disposed at an upstream refrigerant sideof said compressor, for accumulating liquefied refrigerant therein andfor leading gaseous refrigerant into said compressor; and expandingmeans for decompressing and expanding refrigerant, said expanding meansincluding an electric expansion valve which varies the throttling amountof a flow of refrigerant in response to an electric signal so that asub-cool amount of refrigerant passing through said expanding means isvaried in accordance with an air-conditioning load of the automotive airconditioner.
 2. The automotive air conditioner according to claim 1,wherein said expanding means is disposed between said outside heatexchanger and said heater.
 3. The automotive air conditioner accordingto claim 2, wherein said electric expansion valve controls the throttleamount of refrigerant so that the temperature of refrigerant at arefrigerant outlet of said heater has a predetermined super-coolingdegree.
 4. The automotive air conditioner according to claim 1, whereinsaid expanding means is disposed between said outside heat exchanger andsaid evaporator.
 5. The automotive air conditioner according to claim 4,wherein said electric expansion valve controls the throttle amount ofrefrigerant so that the temperature of refrigerant at a refrigerantoutlet of said outside heat exchanger has a predetermined super-coolingdegree.
 6. The automotive air conditioner according to claim 1, whereinsaid electric expansion valve controls the throttle amount ofrefrigerant so that the temperature of refrigerant at an outlet of acondenser has a predetermined super-cooling degree.
 7. An automotive airconditioner, comprising:a duct for introducing conditioned air into aroom of an automobile; a blower for blasting air into said duct; anevaporator disposed in said duct for evaporating refrigerant to coolair; a heater disposed on the downstream side of said evaporator in aflow of air in said duct for causing refrigerant of a high temperatureand air to exchange heat with each other to heat the air; a bypasspassageway disposed on the downstream of said evaporator in said ductfor flowing therethrough air bypassing said heater; an air mixing damperdisposed in said duct for controlling the ratio of a flow rate of air tobe admitted into said heater to a flow rate of air to flow through saidbypass passageway; a compressor driven by an electric motor forcompressing and discharging refrigerant; an outside heat exchangerdisposed for connection between said compressor and said heater forcausing air outside said duct and refrigerant to exchange heat with eachother; expanding means disposed between said heater and said evaporatorfor decompressing and expanding refrigerant; a controller forcontrolling the speed of rotation of said compressor and pivotal motionof said air mixing damper; and at least one of:an outside airtemperature sensor for detecting a temperature of air outside the roomof the automobile; an inside air temperature sensor for detecting atemperature of air inside the room of the automobile; a solar radiationsensor for detecting an amount of solar radiation coming into the room;a blown out air temperature sensor for detecting a temperature of airblown out from said duct; a heater temperature sensor for detecting asignal regarding a temperature of said heater; an evaporator temperaturesensor for detecting a signal regarding a temperature of saidevaporator; and a pressure sensor for detecting a signal regarding apressure of refrigerant discharged from said compressor; said controllercontrolling in response to a signal or signals from the sensor orsensors, the speed of rotation of said compressor and a circuit of saidair mixing damper.
 8. An automotive air conditioner, comprising:a ductdefining a passageway for conditioned air to a room of an automobile; ablower for blasting air towards the room of the automobile by way ofsaid duct; an evaporator disposed in said duct for evaporatingrefrigerant to cool air; a heater disposed on the downstream side ofsaid evaporator in said duct for causing refrigerant of a hightemperature and air to exchange heat with each other to heat the air; abypass passageway disposed on the downstream side of said evaporator forflowing therethrough air bypassing said heater; an air mixing damper forcontrolling a ratio of a flow rate of air to be admitted into saidheater to a flow rate of air to flow through said bypass passageway; acompressor for compressing and discharging refrigerant; an outside heatexchanger for causing air outside said duct and refrigerant to exchangeheat with each other; decompressing means for decompressing andexpanding refrigerant; an evaporator for causing air and refrigerant ofa low temperature to exchange heat to evaporate the refrigerant and coolthe air, whereinin a heating operation, refrigerant flows in the orderof compressor, heater, decompressing means, and outside heat exchanger;in a cooling operation, refrigerant flows in the order of compressor,heater, outside heat exchanger, decompressing means, and evaporator; andin a dehumidifying operation, refrigerant flows in the order of oneof:a) compressor, heater, decompressing means, outside heat exchanger,and evaporator, b) compressor, heater, outside heat exchangerdecompressing means, and evaporator, and c) compressor, heater,decompressing means, outside heat exchanger, decompressing means, andevaporator.
 9. An automotive air conditioner, comprising:a duct definingan air passageway; a blower for blasting air into a room of anautomobile by way of said duct; an evaporator disposed in said duct forevaporating refrigerant to cool air; an evaporator bypass passagewayformed sidewardly of said evaporator in said duct for flowingtherethrough air bypassing said evaporator; an evaporator damperdisposed in said duct for controlling the ratio of a flow rate of air toflow through said evaporator bypass passageway to a flow rate of air toflow through said evaporator; a heater disposed in said duct for causingrefrigerant of a high temperature and air to exchange heat with eachother to heat the air; a heater bypass passageway formed sidewardly ofsaid heater in said duct for flowing therethrough air bypassing saidheater; an air mixing damper disposed in said duct for controlling theratio of a flow rate of air to pass through said heater bypasspassageway to a flow rate of air to flow through said heater; an outsideheat exchanger for causing air outside said duct and refrigerant toexchange heat with each other; a compressor for compressing anddischarging refrigerant; and changing over means for changing over aflow of refrigerant flowing through said outside heat exchanger betweenthe flow of refrigerant which flows to said heater and the flow ofrefrigerant which flows through said evaporator back to said compressor.10. An automotive air conditioner according to claim 9, wherein saidcompressor includes discharging capacity varying means, and furthercomprising a controller for controlling the discharging capacity of saidcompressor, changing over of said changing over means, pivotal motion ofsaid evaporator damper and pivotal motion of said air mixing damper. 11.An automotive air conditioner comprising:a duct defining a passagewayfor conditioned air to a room of an automobile; a condenser disposed insaid duct for condensing refrigerant to heat air; a receiver foraccumulating once therein refrigerant having passed said condenser andfor delivering only liquid refrigerant therefrom; a subcooler disposedin said duct for causing air and refrigerant of a high temperaturedelivered from said receiver to exchange heat with each other to heatthe air; expanding means for decompressing and expanding refrigerantdelivered from said subcooler; an evaporator disposed in said duct forevaporating refrigerant of a low pressure delivered from said expandingmeans to cool air; an outside heat exchanger disposed outside said ductfor causing air outside said duct and refrigerant to exchange heat witheach other; and a compressor for sucking, compressing and dischargingrefrigerant.
 12. An automotive air conditioner according to claim 11,wherein said expanding means varies the throttling amount of arefrigerant passage such that refrigerant on the sucking side of saidcompressor has a predetermined dryness.